DNA Evidence found at Scene

Mark Rollins Criminal Law

DNA evidence

DNA Evidence found at the Scene Does not necessarily mean Guilty

Background of Sample Case

DNA evidence found at the scene?  Lets explore.  Jane Smith, driving in a car that does not belong to her.  She is pulled over by the police.  She was pulled over because the car tags are expired.   Police ask to search the automobile and Jane consents to the search of the vehicle.  Thereafter, to Jane’s surprise a semi automatic gun is found in the car.   The police do DNA testing on the weapon and Jane’s DNA is found on the gun.   So is Jane automatically guilty of possession of the gun?   Not necessary and here’s why

DNA evidence is absolute

DNA, or deoxyribonucleic acid, is the hereditary material in all living things.   Now, DNA is the building blocks of life and usually if your DNA is on an object its very hard to argue that its not your DNA because statistically speaking – well, that’s just not a good argument.  So how can you DNA end up on an object that you may never have touched.    So there are 2 ways your DNA can end up on an object that you never touched.

Biological Material – DNA

So when you speak, cough, sneeze – DNA can be coming out of your mouth and so if you are in car or in a house, its quite possible for your DNA to end up on something.   This would be direct contact between you and the object without actually touching it with your hands.   So even though you never touched the item it is possible because unbeknownst to you it could have come out of your mouth or nose (yes I know pretty nasty).

Secondary Transfer – DNA

The other way your DNA could end up on an object you never touched is by what forensic scientist call secondary transfer.  Secondary transfer means that you could have touched another person (for example by handshake) and then that person touches the gun.  Your DNA could have been transferred from that person to the actual object.


So don’t just assume that since your DNA is on the object in the house or in the car that you will be found guilty.  Its quite possible that your DNA could have landed on the object without your knowledge.  By the way, Jane Smith (name changed) was just aquitted after a jury trial with that same issue.   Have more questions – give us a call.

[wpseo_address show_state=”0″ show_country=”0″ show_phone=”0″ show_phone_2=”0″ show_fax=”0″ show_email=”0″]