Spies aren't the only ones who use infrared imaging. Boston police utilized high-tech tools, including a forward-looking infrared device (FLIR), to find Dzhokhar Tsarnaev hiding in boat under a tarp.
By taking a thermal imaging video from a helicopter, police were able to see Tsarnaev while he was hiding under a tarp, invisible to the naked eye. Thermal, or infrared, imaging is used in a wide variety of industries, including firefighting, security, hunting and building. Such a FLIR camera can be purchased for around $1,000 .