Apply the visible stain powder to an item then anyone who touches it will be stained purple which can last for several days.
 
Apply the UV powder to an item then anyone who touches it will be unknowingly stained. Use a UV flashlight and the part of them exposed to the powder will "glow."
Powder is recommended for indoor use only but for odd angles or outdoor use, you can use petroleum jelly [not included] to create a paste. 
 
Use the UV markers to mark items in the event they are stolen. Then use a UV flashlight and the marked area will "glow." The markers will work on dry surfaces such as currency, metal, paint and glass.
 
The Thief Detection Kit includes:
visible stain powder
UV powder
UV flashlight
(3) UV markers
mixing/storage container
petroleum jelly packet
stir/applicator stick