PARKMAN, Maine — The thickly wooded terrain of this rural town and neighboring communities, where law enforcement personnel on Tuesday continued to search for a local man suspected of killing his ex-girlfriend, makes good camouflage, Piscataquis County Chief Deputy Robert Young said Tuesday.

“It’s thick enough in places that a person 25 feet away is undetectable,” Young said in an email interview.

It’s so thick that Maine law enforcement agencies called in reinforcements from out of state to help search for Robert Glenn Burton, 38, also known as Robert G. Elliot, who is facing a murder charge in connection with the death of his ex-girlfriend, Stephanie Ginn Gebo, on June 5, the day after his probation for previous domestic violence crimes ended.

The sight of additional state troopers driving into the area on Tuesday prompted several residents to voice concerns that something had happened in the case, according to Stephen McCausland, Maine Department of Public Safety spokesman.

“What you are probably referring to are the [New Hampshire] and [Massachusetts] troopers joining the search effort today,” McCausland said at 4:30 p.m. “They began arriving this afternoon. Burton remains at large, and the search continues.”

Piscataquis County Sheriff’s Office personnel were the first to arrive at Ginn Gebo’s home the day her body was discovered and, after securing the scene and interviewing witnesses, identified Burton as a suspect, Young said.

“We spent the first weekend scouring camps and roads in areas we knew he was comfortable with,” the deputy chief said.

Burton is known to local law enforcement, which dealt with him in 2000, for domestic violence terrorizing involving another local woman, and in 2002, when he was on the run for 12 days after threatening the woman’s mother with a rifle and knife before fleeing into the woods.

When he was found at an abandoned camp in Willimantic, it was the Piscataquis County Sheriff’s Office’s negotiation team that convinced Burton to surrender. He went to prison for 10 years, getting out on June 3, 2011, and was put on probation for four years. Burton’s probation ended on June 4, and he is accused of taking Ginn Gebo’s life the following day.

“Burton is very woods wise, and this terrain is thickly wooded, with streams and ponds, hills and old hunting or fishing camps that haven’t been used in years,” Young said.

A memorial service for Ginn Gebo, who had broken off the relationship with Burton a week before her death, was held Friday at her aunt’s house in Parkman. Her body was found in her Kulas Road home by her young children, who are staying with their maternal grandparents. A friend has set up a GoFundMe account to raise money for their care.

Piscataquis County sheriff’s personnel had not been called to Ginn Gebo’s home before her death, Young said.

“We have committed all of our full-time guys [seven, including the sheriff] and some of our part-time guys [five] to this search, as we continue to answer the other calls that come in,” Young said. “We continue to respond to leads and tips as we get them — suspicious persons and vehicles, camps entered or disturbed and that type of thing.”

Maine State Police and the Maine Warden Service have set up an incident command post in the basement of the Parkman town office, McCausland said.

“Although we are not getting into specifics, we feel he is likely still in the area, and the search continues to concentrate in Parkman, Guilford, Abbot, Monson and Willimantic,” McCausland said. “Area residents need to continue to be aware of their surroundings, lock their houses and vehicles, keep outside lights on at night and report anything suspicious.”

The manhunt entered its 12th day Tuesday.

“We are patrolling the back roads,” Young said. “We continue and will continue to work with the state police and warden service in locating Burton and arresting him. The advantage we have is that local folks here know us and are comfortable talking to us.”

Burton is 5 feet 11 inches tall and weighs 180 pounds. He has brown hair and blue eyes, and he sometimes wears glasses.

Anyone who sees Burton should call state police at 973-3700 or 911.