Secret weapon? How thermal imaging helped catch bomb suspect[ Sat, 20 Apr 2013 03:20:58 GMT ]Thermal-imaging devices have been used to seek out pot-growing operations, map Martian geology — and now, to watch the second suspect in this week's Boston Marathon bombings as he was holed up in his last hiding place.Authorities said a helicopter equipped with a thermal imager spotted the heat signature of a person inside a tarp-covered boat, sitting in a backyard in Watertown, Mass. Police used ...