WASHINGTON — Last week, Pennsylvania emergency room doctor Bryan Moles posted a query on his Facebook page: "If you had to choose between a Hilton Hotel and a Trump hotel, which would you choose and why?"

It wasn't clear why he was asking but it appears that Moles, 43, chose the latter. And early Wednesday morning, he was arrested at the Trump International Hotel in Washington, D.C., for having an AR-15 assault rifle , a .40-caliber handgun and 90 rounds of ammunition in his car.

Metropolitan Police Department Chief of Police Peter Newsham said at an afternoon news conference that authorities "averted a potential disaster here in our nation's capital."

But the Secret Service said that an interview with Moles revealed "he posed no immediate threat" to anyone under the agency's protection.

Officials said Moles has given conflicting information about why he traveled to Washington and why he was armed but there's no indication he intended to harm anyone and apparently stayed at the Trump hotel to show support for the president.

Washington Police Chief Peter Newsham, accompanied by Mayor Muriel Bowser, speaks to reporters in Washington on May 31, 2017, after a Pennsylvania physician who was behaving suspiciously and had made threatening remarks was arrested at the Trump International Hotel in Washington. Matthew Barakat / AP

The University of Pittsburgh Medical Center, where Moles is employed, said he had been placed on administrative leave before the incident, but declined to provide details, citing the police investigation.

Friends and family of the arrested man told NBC News they believe the episode can be chalked up to a misunderstanding. They said Moles, a married father of two young boys, is a Navy veteran and a Trump fan who owns guns for protection.

"He is mentally stable in every way, shape or form," said Lisa Dellaratta, a longtime friend who last had contact with Moles through Facebook about a week ago. "There is nothing in Bryan's history or pattern of behavior that would make me think he was a threat at all."

Law enforcement sources told NBC News that a friend of Moles alerted Pennsylvania State Police that she was worried about his state of mind and that he had checked into the Trump hotel in Washington.

Flags fly above the entrance to the new Trump International Hotel on its opening day in Washington, DC, U.S. on September 12, 2016. Kevin Lamarque / Reuters file

Meanwhile, Moles had arrived at the hotel and told staff when he checked in that he had weapons in his car — a violation of district law. Police and Secret Service found the weapons in the car, and Moles was arrested for possession.

He will be charged in court on Thursday and it was not clear if he has retained an attorney. His wife did not respond to requests for comment. Two other relatives, though, said news of his arrest came as a complete shock.

"Everyone around here goes shooting," said one cousin. "I know he had a permit for Pennsylvania. He probably didn't realize it wasn't reciprocated in Washington."

Dellaratta said Moles is a rock-ribbed Republican who delivers home-cooked meals to veterans and recently launched a program to provide K-9 dogs to vets with post-traumatic stress.

"I think this is so blown out of proportion," she said of his arrest. "It's insane."

Pete Williams reported from Washington, D.C., and Tracy Connor and Tom Winter reported from New York