EVIDENCE: The Clues That Remain

🔍 The Clues That Remain

A crime scene can look like a mess.

A broken window. A discarded object. A footprint. A message on a phone. Someone who says they saw something.

But which of these things actually counts as evidence?

The answer is broader than you might think.

Evidence is information or material that can help establish what happened, who was involved, or other facts relevant to an investigation.

Evidence Comes in Many Forms

Evidence doesn't have to be something you can pick up and put in a bag.

It can come from a person, a place, an object, a record or a digital source.

Different types of evidence can tell investigators different things.

Evidence can help answer:

But evidence doesn't always provide a complete answer by itself.

🧱 One Piece Can Change the Picture

Imagine investigators find a muddy shoeprint outside a house.

At first, it might seem like an important clue.

But then they discover:

The garden was recently watered.

Several people had walked through the area.

The shoeprint doesn't match the size of the suspect's shoes.

Suddenly, the print may be much less useful than it first appeared.

Evidence needs context.

📖 Key Word - Evidence

Evidence is information or material that can help establish facts relevant to an investigation.

It can take many forms, and its significance depends on what it can reliably establish.

🔎 LOOK CLOSER

Something can be interesting without being evidence that proves a particular fact.

A person's unusual behaviour might attract attention.

A strange object might raise a question.

A witness might report something suspicious.

These things can help investigators decide what to examine — but they still need to be assessed.

Evidence Has a Story to Tell

Think about a broken window.

The glass might show how it was broken.

Fingerprints might help establish who touched it.

CCTV might show when someone approached it.

A witness might explain what they saw.

Suddenly, several different pieces begin telling parts of the same story.

👉 ROOKIE TIP

Don't ask only “What is it?”

Ask:

“What can it actually tell us?”

⚠️ REMEMBER

Evidence doesn't automatically equal proof.

Investigators need to consider where information came from, whether it is reliable and how it fits with the rest of the evidence.

🧠 Think About It

Investigators find a single fingerprint on a broken window.

Does that prove the person who left it committed the burglary?

Think about your answer before revealing the explanation.

🧩 Rookie Recruit Takeaway

Evidence comes in many forms.

Objects, biological material, witnesses, records and digital information can all contribute to an investigation.

But evidence becomes meaningful when investigators examine it, assess it and understand what it can actually establish.

A clue can raise a question. Evidence helps answer it.

Coming Up Next ➡️

Now that we know what evidence can be, it's time to look at some of the evidence investigators may actually find at a crime scene.

Nextup:

Physical & Biological Evidence ...

🧤 What Can a Crime Scene Leave Behind?

People leave traces behind all the time.

A fingerprint on a surface. A strand of hair on clothing. Blood on the floor. A shoe left behind.

At a crime scene, these ordinary things can become important because they may help investigators work out who was there, what happened and how people or objects came into contact.

Look Around the Scene

Physical and biological evidence can be surprisingly varied.

A single scene might contain several different types at once.

The evidence doesn't necessarily tell investigators the whole story.

It gives them pieces to examine.

They can include:

🧬 Biological Evidence

Biological evidence comes from living organisms or biological material.

Blood is one obvious example.

Other biological material can include saliva, hair with tissue attached, skin cells and other bodily material that may contain DNA.

DNA can be extremely useful, but finding someone's DNA at a location doesn't automatically explain why it is there.

Context matters.

📖 Key Word - DNA

DNA (deoxyribonucleic acid) is genetic material found in most cells of the human body.

Because DNA profiles can be highly individualised, DNA evidence can sometimes help associate biological material with a particular person.

The Contact Principle

When people interact with objects and environments, material can sometimes be transferred.

A person touches a window.

Fibres from clothing may transfer to another surface.

Blood may be deposited during an injury.

These transfers can provide investigators with information about contact and movement.

But transfer alone doesn't necessarily establish exactly what happened.

👉 ROOKIE TIP

Finding someone's evidence at a scene doesn't automatically mean they committed the crime.

Ask how it got there.

🔎 LOOK CLOSER

Imagine a fingerprint is found on a door.

That tells investigators the person touched the door at some point.

But was it:

before the crime?

during the crime?

afterwards?

The fingerprint becomes more useful when investigators consider it alongside the rest of the evidence.

⚠️ REMEMBER

Evidence can show contact without explaining the circumstances of that contact.

Investigators need to consider the location, condition and context of the evidence.

🧠 Think About It

DNA belonging to a person is found inside a house where a burglary occurred.

Can that DNA provide investigators with a useful lead?

Think about your answer before revealing the explanation.

🧩 Rookie Recruit Takeaway

Physical and biological evidence can reveal contact, movement and possible connections between people, objects and places.

Fingerprints, blood, DNA, clothing and other material can all contribute to an investigation.

But evidence doesn't explain itself.

Find it. Examine it. Understand how it got there.

Coming Up Next ➡️

Not all evidence is obvious.

Sometimes investigators are looking for tiny materials that can travel from one place to another without anyone noticing.

Nextup:

Trace Evidence ...

🧵 The Tiny Clues

Some evidence is obvious.

A weapon. A bloodstain. A broken window.

Other evidence can be so small that you might barely notice it.

A tiny fibre on a jacket. A strand of hair. A fragment of glass. Soil caught in a shoe.

These small materials are known as trace evidence.

And sometimes, tiny things can tell a surprisingly big story.

📖 Key Word - Trace Evidence

Trace evidence is small material that can be transferred between people, objects or locations.

It can include fibres, hair, glass, soil, paint and other tiny materials.

This transfer can create connections investigators may not otherwise see.

A Little Material, A Lot of Questions

Imagine a suspect's shoe has a small amount of unusual soil stuck to it.

Investigators find similar soil at a location connected to the crime.

Interesting? Absolutely.

Proof? Not necessarily.

They still need to establish whether the soil is sufficiently similar, how it could have been transferred and whether other evidence supports the connection.

🔎 LOOK CLOSER

Trace evidence is often about connections.

A fibre might connect clothing to a location.

Glass might connect a person to a broken window.

Soil might connect footwear to a particular environment.

The evidence may help investigators ask better questions.

What Might Investigators Find?

The smaller the material, the easier it may be to overlook.

👉 ROOKIE TIP

Tiny doesn't mean unimportant.

Something almost invisible to the naked eye may become useful when examined closely.

⚠️ REMEMBER

Finding the same type of material in two places doesn't automatically prove that the two places are connected.

Investigators need to consider similarity, transfer, location and the wider evidence.

🧠 Think About It

A small piece of blue fabric is found on a broken window.
A suspect owns a blue jacket.

Can the fabric provide investigators with a useful lead?

Think about your answer before revealing the explanation.

🧩 Rookie Recruit Takeaway

Trace evidence may be tiny, but it can help investigators identify possible connections between people, objects and locations.

Fibres, hair, glass, soil and other materials can provide useful information when carefully examined.

Sometimes the smallest clues leave the biggest questions.

Coming Up Next ➡️

Not all evidence comes from a crime scene.

Sometimes the information investigators need is found in what people say, what has been recorded and what has been documented.

Nextup:

Witness & Documentary Evidence ...

📝 The Story Isn't Always at the Crime Scene

Investigators don't only look for evidence at the location of a crime.

Sometimes the answers are found in what people remember, what was recorded, or what was written down.

A witness statement might explain what someone saw.

A photograph might capture a moment.

A receipt might place someone somewhere.

A document might establish what happened before the crime.

Together, these sources can help fill in the story.

People Tell Us What They Know

Witnesses can provide information about what they saw, heard or experienced.

But a witness account is still a person's memory and interpretation of an event.

That's why investigators may compare it with other information.

📖 Key Word - Documentary Evidence

Documentary evidence is information recorded in documents or other recorded material that may help establish facts in an investigation.

This can include records, photographs, messages, reports and other documents.

It can be recorded as:

👁️ Statements • 📸 Photographs • 📄 Documents • 🧾 Records • 💬 Messages

One Event, Different Records

Imagine a burglary is reported at a shop.

A witness says they saw someone leave at 9:15 pm.

CCTV shows a person leaving at 9:12 pm.

A transaction record places the shop owner nearby at 9:10 pm.

None of these pieces should automatically be treated as the complete story.

Instead, investigators can compare them.

Different sources can support each other — or reveal something that needs further investigation.

🔎 LOOK CLOSER

Sometimes the interesting part is a difference between sources.

A witness remembers one time.

A record shows another.

Rather than simply choosing one, investigators can ask:

Why are they different?

The difference itself may need explaining.

👉 ROOKIE TIP

A record can tell you that something happened without necessarily telling you why it happened.

Context still matters.

⚠️ REMEMBER

Investigators still need to understand the circumstances behind the information.

🧠 Think About It

A witness says they saw a person leave a building at 10:00 pm.

CCTV shows someone leaving at 9:55 pm.

Does the five-minute difference automatically mean the witness is lying?

🧩 Rookie Recruit Takeaway

Witnesses, photographs, documents and records can all provide valuable information.

The key is to compare different sources, check inconsistencies and understand the context behind each piece of information.

Don't just collect the story. Check it.

Coming Up Next ➡️

We've seen that evidence can come from many different sources.

But evidence doesn't all establish facts in the same way.

Next, we'll look at the difference between evidence that directly shows something and evidence that allows investigators to reasonably infer it.

Nextup:

Direct vs Circumstantial Evidence ...

🎯 Two Ways Evidence Can Tell Us Something

Imagine a shop is robbed.

A security camera clearly shows a person taking money from the till.

That's one kind of evidence.

Now imagine there is no camera, but investigators find the person's fingerprints inside the till, CCTV places them entering the shop and stolen money is later found in their possession.

That's another kind.

Both can be important but they establish facts in different ways.

Direct Evidence

Direct evidence can establish a fact without needing the investigator to draw an inference from another fact.

For example:

A video recording shows a person taking the money.

The recording directly shows the action.

📖 Key Word - Direct Evidence

Direct evidence is evidence that directly establishes a fact without requiring an inference from another fact.

🧩 Follow the Dots

Circumstantial evidence works differently.

It provides facts from which another fact may reasonably be inferred.

Imagine:

Each fact may be meaningful, but investigators are using those facts to reason towards a possible conclusion.

Evidence can work by:

👁️ Showing a fact directly • 🔗 Connecting facts • 🧠 Supporting an inference • 🧩 Building a bigger picture

🔎 LOOK CLOSER

Circumstantial doesn't mean weak.

Several pieces of circumstantial evidence can combine to create a very strong picture.

For example, a person's location, messages, CCTV footage and physical evidence may each establish different facts.

Together, those facts may support a compelling inference.

👉 ROOKIE TIP

Don't dismiss evidence because it is circumstantial.

Ask:

“What fact does this evidence establish, and what can reasonably be inferred from it?”

⚠️ REMEMBER

Direct and circumstantial evidence aren't simply “strong” versus “weak”.

The strength and significance of evidence depends on the circumstances, reliability and how it fits with the other evidence.

🧠 Think About It

A person's fingerprints are found on the inside of a window that was used to enter a building during a burglary.

Does that directly prove they committed the burglary?

🧩 Rookie Recruit Takeaway

Direct evidence can establish a fact directly.

Circumstantial evidence provides facts from which another fact can reasonably be inferred.

Both can help investigators understand what happened.

Don't just look at the evidence. Look at what it actually establishes.

Coming Up Next ➡️

Evidence can be incredibly useful — but only if it is protected.

Before evidence can be properly examined, investigators need to make sure the crime scene itself is secure.

Nextup:

Securing the Crime Scene ...

🚧 Keep Out!

Police arrive at a suspected crime scene.

People are moving around. A door is open. Objects may have been disturbed. Someone is standing nearby saying they saw what happened.

Before investigators can properly examine the scene, they need to control it.

Why?

Because once evidence is disturbed, it may be difficult or sometimes impossible to put things back exactly as they were.

Who Gets In?

Securing a crime scene isn't necessarily about keeping everyone out forever.

It's about controlling who enters, why they enter and what they do while they're there.

A scene may need to be protected from:

📖 Key Word - Contamination

Contamination occurs when evidence is altered, mixed with other material or affected by something that shouldn't be there.

It can happen accidentally through contact, movement or exposure.

🔒 Think of the Scene as a Time Capsule

A crime scene can contain information about what happened.

A footprint may show movement.

An object may be in a particular position.

A fingerprint may be on a surface.

Blood or other material may be located somewhere significant.

If people walk through the area unnecessarily, they may change the scene before investigators have had a chance to document it.

🔎 LOOK CLOSER

Even someone trying to help can accidentally affect a scene.

A neighbour moves an object out of the way.

A family member cleans a surface.

An officer walks through an area without realising it may contain evidence.

None of these actions necessarily involve bad intentions.

But the scene has still changed.

👉 ROOKIE TIP

Protect first. Investigate second.

The less unnecessary disturbance there is, the more information investigators may be able to recover from the original scene.

One Scene, Many Jobs

• Different people may need access to a crime scene.

• Police may need to make the area safe.

• Paramedics may need to treat an injured person.

• Investigators may need to examine evidence.

• Specialists may later need to collect or analyse material.

The answer isn't simply “nobody goes in.”

It's controlled access.

⚠️ REMEMBER

Securing a crime scene doesn't mean preserving every object exactly where it was forever.

People may need to enter for legitimate reasons.

The goal is to limit unnecessary disturbance and protect evidence as early as possible.

🧠 Think About It

Police arrive at a suspected burglary.

A neighbour has already walked through the house looking for the homeowner.

What should investigators consider?

Think about your answer before revealing the explanation.

🧩 Rookie Recruit Takeaway

Securing a crime scene helps protect the information it contains.

By controlling access and limiting unnecessary disturbance, investigators have a better chance of examining evidence in its original context.

Protect the scene. Protect the evidence.

Coming Up Next ➡️

Even a carefully secured scene isn't completely protected from problems.

Evidence can still be damaged, altered or accidentally contaminated.

Nextup:

Contamination & Preservation ...

🧪 When Evidence Gets Changed

Evidence can be fragile.

A fingerprint can be smudged. A bloodstain can be disturbed. A tiny fibre can disappear. A document can be damaged.

Sometimes this happens accidentally.

That's why preserving evidence is an important part of an investigation.

A Small Mistake Can Matter

• Imagine investigators find a tiny fibre on a piece of clothing.

• Before it can be collected, someone picks up the clothing with bare hands.

• Now investigators have a problem.

• Was the fibre already there?

• Could another fibre have been transferred?

• Has the evidence been altered?

The original evidence hasn't necessarily become useless but its meaning may now be harder to establish.

📖 Key Word - Preservation

Preservation means protecting evidence from damage, contamination, loss or unnecessary alteration so it can be properly examined later.

How Can Evidence Be Affected?

Evidence doesn't have to be deliberately tampered with to be affected.

Evidence can be compromised by:

🖐️ Contact • 💧 Moisture • 🌡️ Environment • 👣 Movement • 📦 Poor storage

🔎 Contamination Doesn't Always Mean Someone Did Something Wrong

A person handling evidence may accidentally transfer their own material onto it.

A wet environment may affect biological evidence.

An item may be stored incorrectly.

A scene may already have been disturbed before police arrive.

Investigators need to consider these possibilities when assessing evidence.

👉 ROOKIE TIP

Ask where the evidence came from and what happened to it before it was examined.

Its history can be just as important as the evidence itself.

Preserving the Original Story

The goal of preservation is to keep evidence as close as possible to its original condition.

That might involve:

• limiting unnecessary handling

• using appropriate protective equipment

• packaging items appropriately

• keeping evidence separated where necessary

• recording how and where it was found

The details matter because investigators may need to explain what happened to the evidence from discovery through to examination.

⚠️ REMEMBER

Evidence can be affected without being destroyed.

A piece of evidence may still be useful after contamination or damage, but investigators need to understand what happened to it and take that into account.

🧠 Think About It

A fingerprint is discovered on a glass door.

Before it can be photographed, someone wipes the door because they think the marks are dirt.

What has happened?

Think about your answer before revealing the explanation.

🧩 Rookie Recruit Takeaway

Evidence needs to be protected, handled carefully and preserved so investigators can understand what it can tell them.

Contamination, damage and poor handling can change evidence or make its meaning harder to establish.

Protect the evidence before you lose the story.

Coming Up Next ➡️

Investigators have found and preserved their evidence.

But there is another question:

How do they record exactly what they found?

Nextup:

Documenting the Evidence ...

📸 If You Didn't Record It, You May Not Be Able to Recreate It

Imagine investigators find a footprint near a broken window.

They don't simply collect it and move on.

They need to record where it was, what it looked like, its size and its relationship to everything around it.

Why?

Because the scene will eventually change.

The evidence may be removed.

Investigators may need to explain what they found weeks, months or even years later.

A Crime Scene Doesn't Stay Still

Once a scene has been examined and evidence collected, it may no longer look the way it did when investigators first arrived.

That's why documentation creates a record of the scene and the evidence as it was found.

Investigators may document:

📖 Key Word - Documentation

Documentation is the process of creating a record of information, observations and evidence during an investigation.

Good documentation helps preserve an accurate account of what investigators found and where they found it.

The More You Record, the More You Can Reconstruct

Consider a footprint.

A photograph can show what it looked like.

A measurement can show its size.

Notes can describe its condition.

A sketch can show where it was located.

Each method records something different.

No single method necessarily captures everything.

🔎 Context Matters

A photograph of a knife on the floor tells you what the knife looked like.

But a photograph showing the knife beside a doorway tells you more about its location.

Add measurements and notes, and investigators have an even clearer record of the scene.

The aim is to preserve context, not just collect pictures of interesting objects.

👉 ROOKIE TIP

When documenting evidence, think:

“Could someone who wasn't here understand what I found?”

That's the standard worth aiming for.

⚠️ REMEMBER

A photograph is a record NOT the entire investigation.

Images, notes, measurements and sketches can work together to create a much fuller picture of the evidence and its location.

🧠 Think About It

Investigators photograph a bloodstain but don't record where it was found or how large it was.

What's missing?

Think about your answer before revealing the explanation.

🧩 Rookie Recruit Takeaway

Documenting evidence creates a lasting record of what investigators found.

Photographs, notes, measurements and sketches can preserve both the evidence and its context.

The scene will change.

The record shouldn't.

Coming Up Next ➡️

You've now followed evidence from the moment investigators discover it through collection, preservation and documentation.

But evidence isn't useful in isolation.

Next, we'll look at how investigators begin connecting evidence to people, places and events.

Nextup:

ACTIVITY - Keep or Discard? ...

Instructions

Investigators have documented eight items from a crime scene. Some may be useful evidence, while others have no apparent connection to the crime.

Decide whether each item should be kept or discarded.

Write the numbers under Keep or Discard on paper or in a separate document. When you have finished, check your answers below.

Keep or Discard?

1. A magazine found inside the property

2. A cigarette butt found near the crime scene

3. CCTV footage showing the street outside the property

4. A takeaway menu delivered six months earlier

5. A muddy shoeprint beside the point of entry

6. A neighbour's complaint about noisy dogs

7. A fingerprint found on the broken window

8. A bloodstain found inside the property