Depending on the way the weapon was used; Fingerprints - skin or hair samples of either the perpetrator OR the victim (if it was used as a club) - the rifling of the barrel of the weapon itself - etc.
the evidence might fade off and would be more difficult to trace the evidence
The toxin would probably not be a useful weapon to distribute over a wide area but might be an effective weapon in other circumstances.
#
trace
Trace evidence in criminal investigations was shown by Dr. Edmond Locard in the early 20th Century.
Yes, forensic scientists analyze and trace various types of evidence found at a crime scene to help solve crimes. This can include analyzing DNA, fingerprints, blood spatter patterns, and other physical evidence to assist in criminal investigations.
This could be trace evidence
The cast of Trace Evidence - 2011 includes: Todd James Jackson as Detective Witt Rob Ullett
At a murder scene, evidence such as DNA, fingerprints, weapons, bloodstains, clothing fibers, and surveillance footage can be found. Additionally, other items like footprints, hair, tire tracks, and any potential trace evidence can be crucial in identifying suspects and building a case.
Sometimes the prepatrator leaves evidence behind that can trace them to the cause. Basically, if there's enough evidence the man or woman left behind, they can be connected to the crime and caught faster.
Trace fossil
The Trace Evidence Unit (TEU) identify and compare trace materials/evidence of specific types that could have been transferred when a violent crime was committed. This is usually in the form of human/animal hair, fibres, fabric, rope, dirt, feather, grass e.t.c.