Lifting days of anxiety for a city and a nation on edge, police captured the surviving Boston Marathon bombing suspect, found bloodied in a backyard boat Friday night less than 24 hours after a wild car chase and gun battle that left his older brother dead and Boston and its suburbs sealed in an extraordinary dragnet. “We got him,” Boston Mayor Tom Menino tweeted. A cheer erupted from a crowd gathered near the scene. “CAPTURED!!!” police added later. “The hunt is over. The search is done. The terror is over. And justice has won. Suspect in custody.” During a long night of violence Thursday and into Friday, brothers Dzhokhar and Tamerlan Tsarnaev killed an MIT police officer, severely wounded another lawman and hurled explosives at police in a desperate getaway attempt, authorities said. Late Friday, less than an hour after authorities said the search for Dzhokhar had proved fruitless, they tracked down the 19-year-old college student holed up in the boat, weakened by a gunshot wound after fleeing on foot from the overnight shootout with police that left 200 spent rounds behind. He was hospitalized in serious condition, unable to be questioned about his motives. Tamerlan Tsarnaev, 26, died in…