How does infrared spectroscopy aid in criminal investigations?
It aids greatly!
Any samples from crime scenes can be placed under Infrared Radiation in order to identify them.
One example of this could be paint left from a car. Investigators can determine the composition of the paint and figure out which vehicles have that specific paint.
Another Example would be if someone found a bullet shell casing at the crime scene. The IR Spectroscopy could be used to determine the composition of the metal in the bullet. From there, investigators could figure out what kind of gun shot the bullet and maybe even what company manufactured it.
To find the postmortem interval (time elapsed since death) IR spectroscopy can be used. In death, a person's bones start to lose water and the proteins begin to decompose.
All of this can be detected. Cool right?