VIDEO: How Boston police tracked bomb suspect

Aerial infrared images showing Dzhokar Tsarnaev in the boat were released by the Massachusetts State Police on Friday.

Theremal images of suspect 370 (photo credit: REUTERS)
Theremal images of suspect 370
(photo credit: REUTERS)
Massachusetts State Police released thermal images Saturday (April 20) of the surviving suspect of the Boston Marathon bombings lying in the stern of a boat in Watertown, Massachusetts.
Dzhokhar Tsarnaev was captured by police after a day-long manhunt on Friday that closed down the city and turned a working-class suburb into a virtual military zone.
Tsarnaev had been hiding in the stern of a boat parked in the backyard of a house in Watertown, police said. A resident called police after spotting blood on the boat.
Aerial infrared images showing Tsarnaev in the boat were released by the Massachusetts State Police on Friday.
                   
Bleeding and in serious condition, he was admitted to a Boston hospital after being captured, a Massachusetts State Police spokesman said.
Monday's (April 15) bombing, described by Obama as an act of terrorism, was the worst such attack on US soil since September 11, 2001, and rattled nerves across the United States.