Proper evidence handling is one of the most important parts of any investigation.

When items are collected at a scene, they must be packaged, labeled, and sealed in a way that protects their integrity. Even a small mistake can create doubt or weaken a case. That is why clear evidence collection procedures are essential for police officers, forensic teams, and anyone responsible for handling crime scene materials.

This guide walks you through the entire process of labeling and sealing evidence bags. You will learn how to prepare the bag, record the right information, and maintain a secure chain of custody. Whether you are new to this work or want a refresher, this step-by-step outline will help you follow proper police evidence bag instructions every time.

 

Why Proper Labeling and Sealing Matter

Clear forensic evidence labeling does more than identify an item. It protects its value during an investigation and in court. When evidence is mislabeled, damaged, or sealed incorrectly, questions may arise about authenticity. A defense attorney can easily point to weak handling as a reason to doubt the findings.

Tamper-evident evidence bags are designed to show if someone has opened or altered them. But even the best bags will not help if labeling is incomplete or the seal is applied incorrectly. Proper documentation supports the entire chain of custody labeling process and shows that each item remained secure from collection to presentation.

 

Types of Evidence Bags You May Use

Evidence bags come in different materials and formats, and the right choice depends on the item being collected.

Paper Evidence Bags

Paper bags allow airflow and reduce moisture buildup. They are best for biological samples like clothing with bodily fluids, items that may mold, and any material that needs to dry naturally.

Plastic Evidence Bags

Plastic bags are useful for non-biological items such as tools, electronics, documents, and drugs. They protect items from dust, dirt, and water, but they should not be used for wet samples because moisture can damage or contaminate evidence.

Tamper-Evident Bags

These bags have built-in security strips or seals that show clear signs if someone attempts to open them. They are used in nearly all modern crime scene evidence bags because they offer an added layer of security.

Whatever type you choose, make sure it is the correct size. A bag that is too small can damage an item, while a bag that is too large may allow movement that could alter fragile evidence.

 

Step 1: Prepare the Evidence Bag

Before touching any item, prepare the bag you will use. This step is often overlooked but prevents cross-contamination and keeps the process organized.

1. Put on gloves and change them whenever necessary.
2. Lay the evidence bag on a clean surface.
3. Check that the bag has no holes, tears, or defects.
4. Confirm that the label area is clean and readable.
5. Write some basic details in pencil first if needed, then finalize with permanent ink.

This early preparation ensures you do not fumble with the bag after picking up the evidence.

 

Step 2: Document the Evidence Before Collection

Evidence collection procedures require complete documentation before anything is moved. This captures the original condition and placement, which can be essential later.

Record the following:

• The exact location of the item
• Its appearance from different angles
• Any identifying marks
• Environmental conditions

Photograph the item with a scale or marker before moving it. These photos support your written record and help others understand the context at the crime scene.

 

Step 3: Collect the Evidence Safely

Once documentation is complete, carefully collect the evidence. Handle items as little as possible and avoid touching surfaces that hold fingerprints, DNA, or trace materials.

Use the right tools, such as:

• Tweezers
• Forceps
• Gloves
• Evidence scoops
• Swabs

Place the item directly into the appropriate bag without shaking or forcing it. For delicate materials, place them in a smaller inner container before bagging.

 

Step 4: Label the Bag with Required Information

This is one of the most important steps. Forensic evidence labeling needs to be clear, complete, and permanent. Use a waterproof, permanent marker to ensure the writing does not fade over time.

Typical police evidence bag instructions require the following information:

1. Case Number

A unique number assigned to the investigation.

2. Item Number

Each piece of evidence receives its own item number to avoid confusion.

3. Description of the Item

Write a short but detailed description. Include color, size, brand, or any special markings.

4. Location Found

Record the exact spot where the evidence was collected. If it was indoors, mention the room or area. If outdoors, describe the surroundings.

5. Date and Time of Collection

This is required for accurate documentation.

6. Collector’s Name and Signature

This identifies the person responsible for collecting the evidence.

7. Agency Information

Include the department name and any relevant contact details.

8. Chain of Custody Labeling Section

Most crime scene evidence bags have a dedicated area for documenting each transfer. Leave this space empty for now. You will fill it out only when the evidence changes hands.

The goal is to make sure anyone viewing the bag later can quickly understand what it contains and where it came from.

 

Step 5: Seal the Evidence Bag Correctly

Sealing the evidence secures it against tampering. Tamper-evident evidence bags have built-in adhesive seals. Once applied, they cannot be opened without leaving obvious marks.

Follow these steps:

1. Remove any air inside the bag, but do not press too hard.
2. Fold the top of the bag according to the instructions.
3. Peel off the protective strip on the adhesive.
4. Press the seal firmly from one end to the other.
5. Make sure the seal is complete with no gaps.

Never use staples or tape unless instructed by your department. These can damage the bag or create confusion about unauthorized access.

 

Step 6: Initial and Date the Seal

After sealing, write your initials and the date across the seal. This shows that you were the one who closed it, and when it happened. If the seal is broken later, the writing will also be broken, which makes tampering easy to spot.

This step adds another layer of security to the chain of custody.

 

Step 7: Complete the Chain of Custody Form

The chain of custody records every person who handles the evidence from collection to courtroom presentation. It proves the item remained secure and unchanged.

Whenever the evidence is transferred, record:

• Name of the person releasing the item
• Name of the receiver
• Date and time of the transfer
• Purpose of the transfer
• Signatures from both parties

This record is often printed directly on police evidence bags or included as a separate form. Never skip or delay this step.

 

Step 8: Store the Evidence Properly

After labeling and sealing, store the bag according to department guidelines. Different items require different storage conditions.

Common storage needs:

• Paper bags with biological samples should be stored in breathable environments.
• Electronic items may need anti-static storage.
• Items requiring refrigeration must be placed in controlled cold storage.

Make sure the storage area is secure and accessible only to authorized personnel.

 

Step 9: Avoid Common Mistakes

Even experienced professionals sometimes make errors during evidence handling. Watch out for these common issues:

Incomplete Labels

Missing dates, signatures, or descriptions can weaken your case.

Incorrect Bag Type

Using plastic for wet items can destroy DNA or encourage mold.

Breaking the Seal

Do not open a sealed bag unless necessary. If it must be opened, record the reason and reseal it with full documentation.

Poor Handling

Touching the wrong part of an item or using the wrong tools can introduce contamination.

Being aware of these mistakes makes the process smoother and more reliable.

 

Final Thoughts

Properly labeling and sealing evidence bags is one of the most important responsibilities in an investigation. Every step, from picking the right bag to signing the chain of custody, matters. Following correct evidence collection procedures helps preserve the integrity of crime scene evidence bags and strengthens the case when it reaches the courtroom.

With careful technique, clear documentation, and consistent handling, you protect the value of every piece of evidence. This guide gives you the foundation you need to follow standard police evidence bag instructions and maintain professional, reliable forensic practices.