BIDDEFORD — Maine State Police say the shooter or shooters responsible for a Sunday night double homicide in Biddeford remain at large.

Lt. Brian McDonough with the Maine State Police told reporters at a Monday afternoon news conference at the 19 Western Ave. location of the crime that investigators are searching for four individuals — two men and two women — who were at the home when the crime occurred.

McDonough also identified the men killed as Russell Lavoie, 42, of Old Orchard Beach and Jeffrey Lude, 37, of Biddeford.

Police say a witness indicated that the four others who were at the home at the time of the shootings fled before they could be questioned.

“It’s early on, but the indication is that these men didn’t shoot each other,” said McDonough.

Each man apparently died of multiple gunshot wounds, he said, although investigators are reconstructing ballistic evidence to determine whether multiple guns or multiple shooters were involved.

McDonough would not comment on whether any firearms — or any other signs of illegal activity, such as drug use — have been found at the Western Avenue home.

“I don’t think this was a random incident,” he said.

Biddeford police received reports of a shooting at the site just after 7 p.m. Sunday and found the victims already wounded.

Crime scene analysts have sectioned off nearly a whole block along Western Avenue with police tape. McDonough said that while the gunfire was believed to have been contained at the residence, investigators are looking for trace evidence left behind by the four individuals who fled the scene.

Moises Cruz III, 21, who lives across the street from the white, three-unit building where the crime took place, said on Monday afternoon that he was “shocked” by the shooting.

Cruz heard six gunshots and saw one of the victims fall, although he said he never saw the shooter.

“There was a heavy-set guy who came out and got shot,” he recalled. “Police showed up on the scene — some people tried to resuscitate him, but they couldn’t.”

Cruz said he didn’t recognize the man he saw gunned down across the street, but said many people often come and go from the multi-unit building.

McDonough told reporters that police believe the shooting began inside the building, but that the activity spilled out onto a side parking area.

Cruz said he did not see the other victim.