WASHINGTON — As officials seek clues about what prompted a Georgia man to fatally stab a Pentagon police officer, details of the suspect’s troubled past emerged Wednesday through interviews and court records.

Austin William Lanz, 27, was arrested in April for a break-in at a neighbor’s home and drew police attention months earlier for an ongoing harassment campaign involving sexually explicit photos and messages, according to interviews and records obtained by The Associated Press.

Investigators have not revealed a motive in the ambush-style killing of Pentagon police Officer George Gonzalez, 37.

But Lanz’s past brushes with the law, and neighbors’ accounts of recent menacing behavior, appear to suggest the violence was more likely the act of a troubled, violence-prone individual than part of a broader conspiracy.

“I wish there was a better way to address those mental health issues that people have,” said Phillip Brent, who shared a backyard fence with Lanz in Georgia and describes repeated harassment directed at himself and his then-fiancée. “It feels like it was just a clear failure of our system to help someone out who needed that help.”

The FBI on Wednesday said the burst of violence began around 10:40 a.m. Tuesday when Lanz exited a bus at the Pentagon Transit Center in Virginia and stabbed Gonzalez without provocation. The two struggled and Lanz shot himself with Gonzalez’s weapon. Other “officers engaged the subject, who ultimately died at the scene,” the FBI said.

Gonzalez was a “die-hard” New York Yankees fan and an Army veteran who served in Iraq and joined the police force in 2018, the Pentagon Force Protection Agency said Wednesday.

The attack temporarily placed the U.S. military headquarters on lockdown and rattled the nerves of a region already primed to be on high alert for violence and potential intruders outside federal government buildings, particularly after the Jan. 6 riot at the U.S. Capitol.

Defense Secretary Lloyd Austin said flags at the Pentagon would be flown at half-staff while the White House saluted Gonzalez as having “lost his life protecting those who protect the nation.”

Investigators were examining Lanz’s background, including his criminal history, jail records, financial information and any online accounts, in search of a motive, a law enforcement official said.

It remained unclear why Lanz picked the Pentagon area for violence. Lanz had enlisted in the Marine Corps in October 2012 but was “administratively separated” less than a month later and never earned the title Marine, the Corps said.

One episode of likely interest to investigators is an April arrest in Cobb County, Georgia, in which Lanz was accused of breaking into Brent’s home in the Atlanta suburb of Acworth in the middle of the night with a crowbar.

He was recorded on video by the security system roaming the house for 13 minutes, turning on all the lights and leaving what were described as “inappropriate photographs and notes.”

He left without taking anything, according to arrest reports and court filings.

After the homeowner provided the video to law enforcement, Lanz was arrested and booked on charges of burglary and trespassing.

When informed he was being charged, Lanz objected to the arresting officer, saying, “but I didn’t take anything,” according to the arrest report.

He then went on to make statements to a police officer about how planes had been flying over the neighborhood and tracking his cellphone.

As he was being processed at the county jail, Lanz is alleged to have attacked two sheriff’s deputies in the intake area without provocation, including one who sustained a chipped bone and torn ligament in her knee. After he was restrained, Lanz reportedly accused the officers of being “gay” for teaming up on him and asked to be uncuffed so he could fight them one-on-one.

A judge reduced his bond in May to $30,000 and released him, imposing some conditions, including that he not take illegal drugs and that he undergo a mental health evaluation. The charges against him are still listed as pending.