Infrared Helicopter Video Of Boston Marathon Bomber Dzhokhar Tsarnaev In Watertown Boat.

Infrared images released by the Massachusetts State Police Air Wing appear to show Boston Marathon bombing suspect Dzhokhar Tsarnaev on Friday, April 19, hiding in a Watertown, Mass., resident's boat in the resident's backyard. Below: A police vehicle uses a boom to inspect the boat.

The moment police found the Boston 'bomber': Extraordinary thermal-imaging photos reveal wounded suspect hiding in a boat Police captured Dzhokhar Tsarnaev, 19, on Friday night after a day-long manhunt using a helicopter with thermal imaging technology Filmed hiding in a covered boat in Watertown by homeowner who ventured out after curfew was lifted He and law enforcement officers engaged in a furious exchange of gun-fire that began shortly after 7pm The stand-off continued until 8.45pm when Tsarnaev surrendered himself to police He was rushed to Beth Israel Deaconess Medical Center where many marathon victims are being treated He was said to be 'clinging to life' this morning as Gov. Deval Patrick says he hopes he survives so he can start answering the 'million' questions awaiting him

Authorities then used a helicopter equipped with a thermal imaging device to confirm that there was a body in the tarp covered boat and that the person was alive.

Hovering over the area, the helicopter spotted the heat signature of a person, confirming Henneberry's suspicions.

'Our helicopter had actually detected the subject in the boat,' Col. Timothy Alben of the Massachusetts State Police told NBC News. 'We have what's called a FLIR ? a forward-looking infrared device ? on that helicopter.

The chopper monitored the body in the boat for more than an hour before police moved in and took the bleeding Dzhokhar Tsarnaev into custody.

He remained in hospital today and was described as clinging to life as Gov. Deval Patrick said: 'I hope he survives, because we have a million questions.'

The secret service's top interrogators are now waiting to quiz him as he is treated in the same hospital where 11 victims are still recovering.

Thermal imagers are able to detect a body or other heat source inside a house, a vehicle, or in this case, a boat, because heat, unlike visible-light wavelengths can pass through walls.

Police regularly use them to find out whether marijuana is being grown inside a house with heat lamps.

A nightmarish 24 hours came to an end in Boston at around 8:45pm yesterday as the 19-year-old suspect was taken into custody alive but injured after a gun battle with police and federal agents.

It signaled the end of five days of terror set-off by the double bombing at the marathon finish line.

The mayor of Boston, Thomas Menino, was quoted by the Boston Globe as taking to the police scanner to exclaim, 'We got him'.

Relieved law enforcement officers began cheering and clapping after he was arrested and thousands of jubilant members of the public took to the streets to salute their hard work.

Dzhokhar's older brother, Tamerlan Tsarnaev, 26, lay dead following a furious fire-fight alongside his younger brother with police on Thursday which left one officer dead.