ROUGH CUT (NO REPORTER NARRATION)br br Police released video of Boston Marathon bombing suspect Dzhokhar Tsarnaev hiding in a boat in a Watertown backyard Sunday. (April 21)br br Tsarnaev, 19, a naturalized U.S. citizen, was found Friday night, covered in blood and hiding on a boat after his brother, Tamerlan Tsarnaev, died after a Thursday night shootout with police that left behind some 250 spent shells on the streets of Watertown, a Boston suburb.br br Federal prosecutors are preparing criminal charges against the 19-year-old suspect in the Boston Marathon bombings who is currently stable but in serious condition and unable to speak, and under heavy guard at a city hospital two days after his dramatic capture.