A man who had been sought almost three years in the Boston Theater District killing of a 22-year-old Army veteran has been arrested in the Dominican Republic.

The U.S. Marshals Service announced Saturday 26-year-old Peter Castillo is in a U.S. jail awaiting transfer to Massachusetts. Castillo had been on the agency's most wanted list.

Police say Perez was shot in the back around 2 a.m. May 10, 2012, after an altercation at a club.

Perez was a former Army sniper who served in Iraq and Afghanistan. He was attending Bunker Hill Community College and planned a law enforcement career.

Boston police issued a homicide warrant for Castillo, who they believed fled to New York then to the Dominican Republic.

Federal authorities say police arrested him Thursday in Santo Domingo.