I have to assume that most experienced officers have noticed that if you are patroling an area at night and you want to drive down a street looking for auto burglars. You shine your spot light towards the roof of the vehicles and the reflection of whom ever is in the vehicle will be seen on the passenger window. you can see if the offenders are armed or just hiding. safe way to check what appears to be abandonded vehicles before approaching them. I caught over 60 auto burglars or auto theft suspects as well as rapist and armed robbers. it works 100 percent of the time. also when tracking a suspect if you pace your steps along side of the suspect you will be able to tell if the suspect is running, or walking. at night place your flashlight paralell to the ground to the track, the track appears to raise and is more visible when tracking. lifting finger prints that you can see but will not adhere to the powder. blow on the print and you will be able to lift print that have been there from a short time to weeks, i always used metalic powder mixed with the black powder this type of mixture will help lift latents from almost any type of surface, including leather shoes. thanks former albuquerque police officer who was given the alpo award for tracking over two hundred felony subjects down and arresting them. was given a can of alpo Woof “Woof”.