It may not always be possible to have a Crime Scene Investigator (CSI) attend a Crime Scene immediately. To ensure that we have the best chance of identifying a suspect and assisting in the detection of a crime, it's important that scenes and forensic evidence is preserved. Here are some things to consider.
Protect the scene
- The point of entry is the place where the offender has entered the scene, and can be a good source of evidence. They may have used force, there may be broken glass, but it is likely they will have made significant contact with this area.
- Try not to touch or disturb any point of entry or exit, because this will give the investigators the best chance of finding forensic evidence that may identify or link a suspect to the scene.
Have items been left by the offender?
- After an offender has left the scene they may drop or leave things. Items that may be left could be cigarette butts, tools, items of clothing, drinking vessels or food - of course, they could leave anything at all, so keep an eye out for items you don't recognise.


- Wherever possible, items should be left in situ where they are found. This is becuase handling or moving items can disturb fragile evidence. Even if gloves are worn (or below instuctions are followed), care must be taken not to over handle items.
There may be times that leaving items in situ may result in losing evidence that may be present, for instance if the item is outside and it is raining heavily, or is in a public area where the integrity of the item would be compromised by leaving it where it is. In these circumstances, carefully moving the items to further protect them is recomended.
How to preserve an item that can be kept outside:
- If an item can be left outside while waiting for CSI to attend, then try to do so as the context and the location of the object may be important to the investigation.
- If an item is outside, place an empty clean rigid container over the top of the item (e.g. bucket or washing up bowl) ensuring that it can't be disturbed by the weather, people or pets.


- If the empty clean rigid container isn't heavy enough and you believe it's going to be easily moved due to weather conditions, place a heavy object on top of the bucket to add a bit of weight - however, make sure that it's not too heavy that the empty clean rigid container breaks.
How to preserve an item that needs to be brought inside:
- If you believe that an item has been left outside and it is not safe, could be contaminated or lost, or due to severe weather conditions, then the item can be brought inside.
- Place a clean and unused bag (for example, a bin liner, carrier bag, food bag etc) over your hand before picking up/touching the item. Imagine your picking up something you really don't want to be touching!

Then, using your other hand, move the bag over the item and off your hand, ensuring the bag is covering it so that no one can touch it. Doing this decreases the chance of contamination and preserves the item.


- Once the item has been preserved it can then be brought within the premises. Keep it in a safe location that can't be touched until CSI attend the scene.
Are there visible footprints?
Is there a visible footprint at the crime scene left behind by the suspect(s)? Can you see the pattern of the sole of the shoe?

How to preserve the footprint
- Find a washing up bowl, bucket or something similar that can be placed over the footrpint to protect it from the weather or being disturbed. Ensure it is big enough to cover the whole print.
- Place the bowl or similar over the top of the footprint.

- (In the case of a footprint in snow please do not cover it as it may melt)
- If the bowl is likely to blow away, place something heavy on top like a stone or similar to keep it in position.
- If the footprint is inside, please use the same method and/or try and stay away from the area ensuring it is not disturbed by children or pets.
Have you spotted blood or visible fingerprints?
Has the suspect cut themselves? Is there any blood present at the scene of the crime? Is there a visible fingerprint at the crime scene (perhaps on some glass or a highly polished surface?)


How to preserve the blood or fingerprints
- If you notice that there is blood before contacting 101, then let the call handler know so that CSI Officers are aware that there is a DNA potential at the location.
- If possible avoid disturbing the area where the evidence is, keeping children and pets away from it.
- If it is outside and you believe the evidence may be lost, please tell the call handler on 101.