A Salem man was sentenced on Monday to life in prison without the possibility of parole for the 2012 murder of a 22-year-old U.S. Army veteran in Boston's Theater District.

Peter Castillo, 28, was convicted of first-degree murder last week for the death of Stephen Perez, who officials say was gunned down during an altercation in a Theater District parking garage. 

“Cases like this are the reason we take a hard line against illegal handguns in Boston,” said Suffolk District Attorney Daniel F. Conley in a statement. “A young man carrying an illegal handgun isn’t just more likely to use it — he’s more likely to put himself in the position where he’ll use it. This was an argument, a fistfight at the most, that escalated to murder because the defendant was carrying a handgun he had no business possessing. And the terrible irony is that Stephen Perez survived two tours of duty in Afghanistan only to die on the streets of Boston.”

After that 2012 incident, Perez was rushed to Tufts Medical Center where he was pronounced dead and Castillo fled the scene and later the country, according to the DA's office.

After adding him to their 15 most wanted fugitives list, the U.S. Marshals Service captured Castillo in the Dominican Republic in January 2015.

At the sentencing on Monday, Perez's friends and family remembered him as warm, loving and a "most loyal son, brother and friend."

"It is impossible to relay to the court the amazing character of this beautiful young man," Amanda Prouty, Perez's sister, wrote in an impact statement. "In the military, Stephen made countless sacrifices to better the lives and ensure the safety of the people in this country, but beyond that Stephen touched the lives of anyone who was lucky enough to be around him, in the most positive and uplifting way possible. He truly was the light of our lives. Our hearts have never been more dark."

Luis Sepulveda and Janice Hardy, both of Lynn, were also charged in connection with the case for allegedly lying to police and then to the grand jury investigating Perez's murder. They will be tried at a later date.