As law enforcement in Pennsylvania near the 72-hour mark in the ongoing search for escaped inmate, Michael Burham, Fox News has learned details on the skillset and circumstances which may have helped Burham evade arrest thus far.
A source close to the investigation tells Fox News, Burham has firearms training and several family members located in neighboring states to Pennsylvania.
The new information comes as Pennsylvania State Police caution those who live nearby, or visit the area of Warren County to heed Burham as "extremely dangerous."
Burham is described as a "survivalist" by state police, who also indicated they’d found evidence suggesting the escaped inmate may still be in the area.
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"We have located some small stockpiles or campsites in wooded areas in the general vicinity of Warren," Pennsylvania State Police Lt. Col. George Bivens said. "It supports what we’ve said all along, that he’s prepared as a survivalist in the past and tried to be ready, if you will, to spend time in the woods."
Burham could be receiving help from others, too.
"I think that it's entirely possible that he may be getting some assistance," Bivens said.
Burham escaped from the Warren County Jail late Thursday night. Investigators said he climbed on top of exercise equipment to access the roof of the jail, and then used a makeshift rope to scale down.
Another law enforcement source confirmed to Fox that the makeshift rope stretched from the roof of the building to a backdoor awning – leaving only a short distance for Burham to jump to the ground and flee.
Shortly after news of the escape first broke, a spokesperson for Warren County said Burham would've been "restrained" when moving around the facility but wasn't in the exercise yard.
"In order to only allow a certain number of inmates [out] in that exercise area at any one time, they've got to have a schedule," Bivens said on Sunday. "That schedule runs very early in the morning to very late at night in order to be able to properly accommodate the legal requirements for yard time for the inmates."
The jail is just outside the Allegheny National Forest; Bivens said the search had gone a "significant" distance into the forest, but he declined to provide further specifics on the search area, only reiterating that everyone who visits the area should be vigilant.
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"This is an area that people from outside the area come to for hiking and kayaking, canoeing." Bivens said. "It’s hard to say what his mindset is, whether anyone is in additional danger. I do think that not only him, but anyone in this situation becomes more desperate over time.
State police have used infrared technology, helicopters and drones to search for Burham through the densely wooded terrain.
Sunday, not far from the jail, U.S. Marshals surveyed and then later, entered a home with guns drawn. A source told Fox News police had received a tip about movement inside the vacant property.
Investigators said based on Burham’s previous behaviors, it’s possible he could’ve secured a firearm or other weapons at this point.
This is the second time there’s been a manhunt for Burham.
In May, after Kala Hodgkin was gunned down in New York near the Pennsylvania border, investigators said Burham fled the area after being named a suspect.
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Officers said he went on an interstate crime spree – which included the kidnapping of an elderly couple at gunpoint, and other crimes, according to a criminal complaint filed by the FBI.
Burham was eventually arrested in South Carolina on May 24 and had been held in the Warren County Jail on arson and burglary charges until this recent escape.
A combined $9,500 reward is being offered through the U.S. Marshals Service and Warren County Crime Stoppers.
Anyone with information on Burham’s whereabouts is asked to contact Pennsylvania State Police at 815-728-3600.
Fox News' Jennifer Johnson contributed to this report.