Mr. Manson and other senior agents were in Charlotte for training, according to a law enforcement official familiar with the episode. The agents later told the police that they had been drinking with women who said they were exotic dancers, according to a second person who was briefed on the investigation but, like the first, was not authorized to discuss it publicly.

“Investigators determined that the victim, Robert Manson, met a woman in the hotel bar the prior night and took her back to his hotel room,” Robert Tufano, a spokesman for the Charlotte-Mecklenburg Police Department, said in a statement.

At 6:30 the next morning, police officers for the department were called to the hotel. Mr. Manson was incapacitated because of alcohol, according to the police report, which he did not file himself. A fellow agent, Kevin Thuman, gave the report, which says the theft happened from 2 a.m. to 5 a.m. The hotel bar closes at 2 a.m.

The gun was identified in the police report as a Glock 27, a compact model that is easy to conceal. Federal law allows agents to carry concealed weapons while off duty, but not while they are intoxicated. It is unclear where Mr. Manson kept the gun. F.B.I. rules prohibit agents from leaving their guns in unsecure places. Every room in the Westin is equipped with a safe.