A convicted killer’s abandoned truck could offer clues about his next move after he escaped a Tennessee prison and triggered a multi-state manhunt, a former FBI special agent told Fox News Digital.

Jacob Allen Morley broke out of the Northwest Correctional Complex in Tiptonville, Tennessee, on Sunday, although authorities have not disclosed the precise time of his escape. Staff at the prison noticed Morley was unaccounted for at around 11:30 p.m., and a review of surveillance footage subsequently revealed him crossing through the facility's perimeter fence.

Surveillance footage recorded Morley taking a pickup truck from the 400 block of Keystone Drive at around 1 a.m. Monday, a location roughly two miles south of the prison, the Tennessee Bureau of Investigation said. The truck was found abandoned by law enforcement officials on early Tuesday morning in Marion, Illinois, but Morley wasn't located.

The manhunt has drawn assistance from multiple agencies, with an Illinois State Police spokeswoman telling Fox News Digital that the agency has "offered its assistance to the Tennessee Bureau of Investigation." TBI separately confirmed that the U.S. Marshals Service is assisting in the search for Morley.

Retired FBI special agent Jonathan Gilliam told Fox News Digital he thinks the abandoned truck offers clues to what Morley's next move might be.

"But when he got the truck, now they found that two and a half hours north, he is probably gonna lay low or he's gonna try to get another vehicle," Gilliam said.

"That vehicle in particular that he took is a work truck [that] just absolutely screamed work truck," he added, saying it "would have been easy to identify." Gilliam said if Morley managed to steal another truck that isn't as identifiable as the work truck, it could dramatically expand the search area.

"If he's in a vehicle that's nondescript and nobody reports it missing, he could go a very long ways without being caught," Gilliam said. "He could be halfway across the country." Gilliam said Morley’s lack of money could ultimately limit how far he can travel, unless he obtains additional resources by committing another crime. Unless Morley is receiving outside help, something authorities have not indicated, Gilliam said his movements suggest he may simply be trying to put as much distance as possible between himself and the prison.

"I think the fact that this guy went north reduces his chance of familiar resources. So family resources are all east. He went north," Gilliam said. "If I had to just look at the totality of what I know right now at this point, I would think that the guy is probably more just trying to put distance between him and the prison." Morley is described as 5 feet, 11 inches tall and weighing 240 pounds, with brown hair and green eyes. The Tennessee Bureau of Investigation said he should be "considered dangerous," adding Morley is now on the state's most wanted list.

In addition to the first-degree murder conviction, he was also found guilty of burglary, vandalism, tampering with evidence and evading arrest. Both federal and state law enforcement agencies are assisting in the search for Morley, officials said. Morley was serving a life sentence for the 2022 murder of Cody Birchfield.

Birchfield disappeared in early February 2022 after he was last seen in Elizabethton, Tennessee. According to WJHL, investigators from the Carter County Sheriff's Office saw indications that a "violent crime" had occurred inside his house.

On March 2, 2022, Morley was arrested after a police chase that went to the North Carolina state line. After the arrest, Birchfield's body was found underneath Morley's home.

Morley's former girlfriend, Landree Sheperd, testified at Morley's trial and claimed that the defendant said at one point that "he f---ing killed him." People with information about Morley's whereabouts are encouraged to contact 844-832-3463.