Maine State Police released a new document Tuesday afternoon that suggests the gunman who killed 18 people in Lewiston last October may have been stalking the overflow lot at Maine Recycling Corp. in Lisbon, intending to ambush his former co-workers.

The report from the Department of Homeland Security describes officials’ attempts to obtain surveillance footage and suggests that Robert Card may have been planning to attack former co-workers from the parking lot, where his body was discovered 48 hours after he committed Maine’s deadliest mass shooting, killing 18 people and wounding another 13.

Though there were cameras at the main recycling facility, there were none at the overflow lot, according to the report. Card, who previously worked at the facility, “would have known” that there were no cameras there, an unnamed source at the facility told Homeland Security officers Special Agent Ryan Maher and Task Force Officer Marshall McCamish days after the shooting.

That source, whose name was redacted from the published report, “also advised that he believes Card specifically chose the tractor trailer where his body was found to set up an ambush.” Recycling facility employees were supposed to park in the overflow lot, according to the report, meaning their vehicles would only be a few feet away from the trailer.

Maher and McCamish attempted to obtain surveillance footage from a dozen businesses around Capital Avenue in Lisbon on Oct. 28, the report said. Half those businesses lacked operational cameras.

That same day, Special Agent and Computer Forensics Agent Christopher Bennett and Special Agent Chase Ossinger pursued surveillance footage from around the intersection of South Avenue and Lisbon Street and along River Road in Lewiston.

They believed those cameras may have recorded Card’s vehicle traveling from Schemengees Bar and Grille to a boat launch in Lisbon, according to the Homeland Security report.

A camera at River Road Agricultural in Lewiston captured the “potential sighting” of Card’s vehicle – a white Subaru – around 7:12 p.m. the night of the shooting, the officers said in their report.

Police were able to trace some of Card’s journey from Schemengees via a collection of video surveillance, the commission charged with investigating the shooting noted in its final report, which was released last week.

But there were no cameras at the boat launch, the commission said. Though there was another camera on a nearby recreational path, it was not working that evening, according to the commission.

Police began searching the overflow lot where Card’s body was found the night of the shooting but called off the effort due in part to insufficient backup and equipment, the commission said.

The next day, Homeland Security Special Agent Martin Conley heard from an unnamed individual that “law enforcement needs to check the area around the redemption center,” Conley stated in his report, part of the report released Tuesday. That other individual’s name was also redacted.

“Conley asked [redacted] [if] he related this information to State Detectives at his house. [Redacted] said he mentioned it repeatedly.”

Card’s brother and the manager of the recycling center also told police about the overflow parking lot, the commission said in its final report.

Still, that information was not passed to the commander of the manhunt team, and nearly two days went by before authorities found Card’s body.