Man who threatened to kill Trump considered armed and dangerous: Law enforcement The Pennsylvania man has been wanted since June.

A Pennsylvania man who threatened to kill President Donald Trump back in June is still on the run and was last seen in Cumberland, Maryland, earlier this week in a stolen truck, the U.S. Marshals Service said.

A warrant was issued June 19 for 27-year-old Shawn Richard Christy and he remains wanted by federal authorities for threatening other elected officials as well.

According to court documents, Christy, in a threatening post on Facebook to Northampton County, Pennsylvania District Attorney John Morganelli, wrote: “Keep it up Morganelli, I promise I’ll put a bullet in your head as soon as I put one in the head of President Donald J. Trump.”

Supervisory Deputy U.S. Marshal Robert Clark told ABC News the stolen red pickup truck was recovered Tuesday, in Tamaqua, Pennsylvania, near Christy's hometown of McAdoo.

Christy is considered by the U.S. Marshals, FBI and U.S. Secret Service to be armed and dangerous.

Authorities say Christy has a distinct lisp and a barbed wire cross tattoo on his upper right arm. He also, according to authorities, considers himself a survivalist.

Christy also said that he was going to use "lethal force" on any law enforcement attempting to detain him. He made the comments between June 3-12.

The reward for any information is now up to $20,000 and the three agencies are asking for the public's help with any information leading to Christy.

He is also wanted in Pennsylvania for burglary, probation violation and failure to appear for an aggravated assault case.

"Persons having information should contact the U.S. Marshals at 1-877-Wanted-2 (1-877-926-8332) or the FBI at 215-418-4000," a release from the Marshals said.

"Individuals should not attempt to arrest Christy themselves," the release said.

This is not the only time Christy has made threats against a public official.

In an interview with Newsweek, Shawn Christy's father, Craig, said that his son explained to him how he hid from law enforcement and noted that he has various guns on his possession that he had taken from the home.

Last year, according to the Associated Press he swung a stick at the McAdoo mayor over a dispute about snow plowing.

He's also had problems with former Alaska governor and vice presidential candidate Sarah Palin, who filed a restraining order against then 18-year-old Christy in 2010.

A year later he pleaded guilty to making harassing phone calls to Palin, her family members and lawyers.

"This is one of the stalkers who has tormented my family for years. Threatening my kids and my parents, following my daughters, moving to Alaska, then following Bristol to Texas to more aggressively physically invade and intimidate... it’s been a hellish ride with these stalkers... as we’ve informed the FBI and law enforcement for years," Palin said in a Facebook post August 20.

"Finally, perhaps, in this particular case with one of the stalkers - Shawn Christy (having recently threatened the President) justice may prevail."

ABC News' Jack Date contributed to this report.