WASHINGTON — Troubling new details emerged Tuesday about the psychological state of Aaron Alexis, accused of killing 13 people on Monday at the Navy Yard complex, and how his life appeared to suddenly unravel.Among the revelations: Alexis legally purchased a Remington 870 12-gauge shotgun Saturday, two days before the shooting, in Lorton, Va. Also, a new police report said Alexis was hearing voices, and Navy officials said the former reservist racked up at least five infractions while spending nearly four years in the Navy reserve, much of it in Fort Worth.Alexis, 34, apparently passed all the background checks required in Virginia to buy the weapon. That raised new questions because of two prior arrests for gun-related incidents in Washington state and in Fort Worth and, more importantly, what appears to have been a psychotic break little more than a month before the killings.An Aug. 7 police report filed by Newport, R.I., officers, which was released Tuesday, said they were dispatched to a Marriott hotel after Alexis called about being harassed. He explained that he’d been in an argument before boarding a flight from Virginia and that two men and a woman were sent to follow him “and keep him awake by talking to him and sending vibrations into his body.”Alexis told the officers that he “first heard [the voices] talking to him through a wall while at the Residence Inn.” It said he’d switched to a hotel at a naval base before taking a room at the Marriott, where the voices were coming through the floor and ceiling, and that individuals who he feared would harm him were using “some sort of microwave machine” to send vibrations.The officers’ report said the naval station police were notified, and local police were advised that there would be a follow-up to determine whether Alexis was actually a defense contractor. Friends of Alexis in Fort Worth, where he had lived until August, said Tuesday that they saw no sign of his deteriorating health.White Settlement restaurant owner Nutpisit Suthamtewakul, with whom Alexis lived for three years, said he was aware that his friend had gone to a VA hospital for a foot injury, but said he knew nothing about any visits to a mental health professional. He said Alexis, 34, never mentioned that he heard voices, a sentiment echoed by another local friend, Melinda Downs.Suthamtewakul said he knew that Alexis carried a gun but never feared for his life.“If he had angry problems, or mental problems, I should have been the one he killed, because sometimes I make him mad,” Suthamtewakul said. “I mean, I lived with him for three years. I know he had a gun. If I felt threatened or unsafe, I’d be the one to move out.”‘He watched my back’However, in July, Suthamtewakul accused Alexis of pouring sugar and water into his gas tank, disabling his car, a day after the two had a confrontation, according to a Fort Worth police report. Suthamtewakul told officers that the two had been having escalating problems, prompting him to ask Alexis to move out, according to Cpl. Tracey Knight, a Fort Worth police spokeswoman.“They’d gotten in a confrontation the previous day and then his vehicle wouldn’t work,” Knight said.Suthamtewakul said Tuesday that he now doubts that Alexis did anything to his car.“I did that because my wife said we should have some evidence if that happens again,” he said. “He’s my friend and we were friends a long time. He watched my back.”After moving out in mid-July, Alexis lived with Downs before moving to the Washington, D.C., area in August.Honorable dischargeAlexis was given an honorable discharge from the Navy after nearly four years as a full-time reservist, much of it in Fort Worth, according to a Navy official who asked not to be identified.A petty officer 3rd class, Alexis had worked with the Fleet Logistics Squadron VR-46 at Naval Air Station Fort Worth from 2008 until being discharged on Jan. 31, 2011.Alexis was given an early release because he had at least five instances of military offenses, including unauthorized absence from work, insubordination, instance of being away without leave, or AWOL, disorderly conduct and room inspection failure, according to the Navy official.“It can be something of a nitpicky thing. But if someone fails an inspection, that may mean that they spend a couple of days on base they didn’t plan on spending. They can use it as a positive thing. They urge the person to clean themselves up and improve,” the Navy official said. Alexis applied for the early discharge through an early enlisted transition program. Friends said Alexis told them he left the Navy because he didn’t like getting up early.After leaving the Navy, he spent much of his time at Suthamtewakul‘s Happy Bowl Thai restaurant in White Settlement, where he helped out as a waiter.He later got a job as an information technology specialist with defense subcontractor The Experts.At an afternoon news conference, the FBI also offered new details about Alexis’ final days.He’s now thought to have arrived in the Washington area around Aug. 25 and stayed in area hotels. On Sept. 7, he checked into a Residence Inn not far from the Navy Yard in the southwestern portion of Washington.“We continue to conduct interviews, exploit digital media and run down every lead we can to piece together his recent movements and to determine the motive behind his attack,” said Parlave, who asked the public to share any and all information that’s known about Alexis. “No piece of information is too small.”While Alexis was serving in the Navy as a reservist, he had civilian arrests, including one in Georgia on a disorderly conduct charge and one in Texas for discharge of a firearm. There was a third arrest in Seattle, which predated his naval career, for shooting the tires of a parked car.The FBI declined to comment on multiple but unconfirmed reports that Alexis had suffered a psychotic break and sought treatment from Veterans Affairs and reports about his misconduct in the Navy.“We continue to look into Mr. Alexis’ past, including his medical and criminal histories,” Parlave said, declining to comment further. Star-Telegram staff writers Bill Miller contributed to this report along with McClatchy Washington bureau writers Jonathan S. Landay, James Rosen, Greg Gordon, Marisa Taylor, Lindsay Wise and Maria Recio.