Can DNA place someone at a crime scene?

No.

DNA alone cannot determine that a person was present at a crime scene.

DNA testing can identify biological material and sometimes link it to an individual, but it does not establish how that material was deposited, when it was left, or whether the person was physically present at the time of the alleged event.

DNA may be present at a location for many reasons. It can result from prior contact, indirect transfer through people or objects, persistence on surfaces, or movement after deposition. In some cases, DNA may appear somewhere even if the person has never attended that location.

Laboratory testing can detect DNA on an item or surface, but it cannot determine the pathway by which it arrived. It cannot distinguish between direct presence at a scene and indirect transfer through intermediary individuals, clothing, or objects.

Research has shown that DNA can persist and move between environments, meaning that its presence does not necessarily reflect when it was deposited or whether it relates to the alleged event.