State Police Release Video of Suspect in Boat, Flash Grenades Going Off

(Courtesy: Mass. State Police)

(Courtesy: Mass. State Police)

WATERTOWN, Mass. (CNN) — Massachusetts authorities have released this helicopter video from Mass. State Police

It shows the boat where 19-year-old Dzhokar Tsarnaev finally surrendered to police Friday night.

The thermal images show the suspect curled up inside the boat. The image of the boat and yard appear white.

Police say that the dark figure inside was the suspect.

At a couple points, you can see flash grenades go off inside the boat, placed in the boat by law enforcement.

The aerial video helped police figure out where Tsarnaev was on the boat and how they might get him out.