A Salem man has been indicted by a Suffolk grand jury for allegedly killing Army veteran Stephen Perez in April, prosecutors announced Thursday.

The grand jury indicted ­Peter Castillo, 23, on charges of first-degree murder and unlawful possession of a firearm Wednesday, according to Suffolk District Attorney Daniel F. Conley's office. Several agencies, including the US Marshals Service, are actively searching for Castillo, officials said.

Around 2 a.m. on April 28, police responded to a 911 call reporting that a man had been shot at 290 Tremont St., near Eliot Norton Park in the Tufts Medical Center area. Officers found Perez, 22, outside suffering from a gunshot wound. He was transported to Tufts Medical Center, where he was pronounced dead.

On June 7, authorities identified Castillo as a suspect in the homicide after obtaining a warrant charging him with murder. A month earlier, Boston police had released surveillance footage from the area in an attempt to identify the assailant.

Perez served in the Army as a sniper during deployments to Iraq and Afghanistan, friends and family said.

If Castillo is apprehended, he would be arraigned in Suffolk Superior Court.