He packed up and went to an unidentified hotel on a Navy base in Newport where he heard the same voices talking to him. He moved to a third hotel, the Marriott, according to the police report. There, Alexis first told authorities that the three individuals spoke to him through the floor and then the ceiling.
Alexis said the individuals were using "some sort of microwave machine" that sent "vibrations through the ceiling, penetrating his body so he cannot fall asleep." He told authorities, according to the police report, that "he does not have a history of mental illness in his family and that he never had any sort of mental episode."
Newport police said they referred the matter to the Newport naval base. That facility on Tuesday deferred comment to the FBI, which would not speak about the report.
Alexis is believed to have arrived in the Washington area last week, when he checked into a hotel, according to someone who met him at the hotel. The person, who declined to be identified, said Alexis indicated he planned to be in the area for several weeks.
At the time of the shooting, Alexis was working for The Experts, a subcontractor of HP Enterprise Services that was contracted to "refresh equipment used on the Navy Marine Corps Intranet network," according to a statement released by the company.
Alexis, who had Department of Defense security clearance, worked from September 2012 through January refreshing computer systems in Japan, said Thomas E. Hoshko, the CEO of The Experts.
His security clearance was renewed in July to carry out the same type of contract work at the Navy Yard, Hoshko said.
Alexis returned to work with The Experts that same month, he said. He worked at facilities in Rhode Island, North Carolina and Virginia for weeks at a time upgrading computer systems, Hoshko said.
No one reported having any problems with him during those assignments, the chief executive said.
Alexis began working at the Navy Yard last week, though it was unclear whether he had actually begun working or was still securing his base clearance, Hoshko said.
Alexis served as a full-time Navy reservist between 2007 and 2011, according to military records. He achieved the rank of aviation electrician's mate 3rd class, working on aircraft electrical systems, the records show.
From February 2001 until February 2003, he worked for the Borough of Manhattan Community College as a college assistant in the administrative computing office, according to spokesman Barry Rosen.
Barry Williams, who was Alexis' supervisor there, said the suspect become easily frustrated over small things and could hold a grudge, but that he never saw him get violent.
Alexis, who managed switches and networking in the office, was a better than average worker, Williams said.
While the FBI are urging anyone with information about Alexis to come forward, investigators are focusing on reported incidents, including police run-ins, that portray a man with increasingly violent tendencies.
There were no indications that Alexis had any ideological differences with the Navy or any disagreements with anyone at the Navy Yard, according to a U.S. law enforcement official with knowledge of the investigation.
Alexis' family reeled at the news that he is believed to be the man behind the killings.
"What I do know is he wasn't that type of person," Anthony Little, who identified himself as Alexis' brother-in-law, told reporters outside his home in the Brooklyn borough of New York City. "I didn't really hear anything that would make me feel, as a newcomer to the family, that somebody should be watching him."