PORTLAND – Mercy Hospital is offering a $20,000 reward for information leading to the arrest and indictment of those responsible for killing an unarmed guard.

Eileen Skinner, Mercy’s chief executive officer, said she hopes the reward will motivate someone to come forward to help police find those responsible for the killing of James Angelo, who was shot in the back early Sunday while on break in a hospital parking lot

“One of our strong Mercy values is justice, and we think that as a matter of justice it’s important for us to do something to help our police department find the individuals who did this,” Skinner said Thursday at a news conference at the Portland Police Department.

Interim Police Chief Joseph Loughlin said Thursday that witnesses and video surveillance captured two assailants running away after Angelo was shot.

Police are searching for the two people, one of them described as a short, clean-shaven black man in his 20s and with a slight build. He was wearing black pants and a white, hooded sweat shirt. The other person was described as wearing a light-colored shirt or jacket.

Detectives have some strong leads in the case, but they can be helped if individuals who know about the case come forward, Loughlin said.

“This is an insult to the entire community, and this city and its citizens should be vested in determining what happened here,” he said.

The video surveillance shows Angelo being approached by two people at about 4 a.m. Sunday. Angelo was shot as he turned away from them. Angelo, who was hit in his upper back near the base of his neck, died a couple of hours later at Maine Medical Center.

Mercy Hospital security has been boosted since the shooting, and there are plans to hire an off-duty Portland police officer for the hospital emergency room, Skinner said. But there are no plans to arm the hospital’s security staff, she said.

Angelo’s funeral, planned for Saturday, will feature a procession to the Cathedral of the Immaculate Conception. Among those participating will be members of a youth soccer team Angelo used to coach. The team plans to march behind the hearse.