LAS VEGAS — An Army soldier who fatally shot himself in a Tesla Cybertruck just before it exploded outside the Trump hotel in Las Vegas on New Year’s Day left notes saying it was stunt to serve as a “wakeup call” for the country’s ills, investigators said Friday.

Matthew Livelsberger, a 37-year-old Green Beret from Colorado Springs, Colorado, also wrote in the note that he needed to “cleanse my mind” of the lives lost of people he knew and “the burden of the lives I took.”

Livelsberger apparently harbored no ill will toward President-elect Donald Trump, Las Vegas Metropolitan Police Department officials said.

“Although this incident is more public and more sensational than usual, it ultimately appears to be a tragic case of suicide involving a heavily decorated combat veteran who was struggling with PTSD and other issues,” FBI Special Agent In Charge Spencer Evans said at a news conference.

The explosion caused minor injuries to seven people but virtually no damage to the Trump International Hotel. Authorities said Friday that Livelsberger acted alone.

“This was not a terrorist attack, it was a wakeup call. Americans only pay attention to spectacles and violence. What better way to get my point across than a stunt with fireworks and explosives,” Livelsberger wrote in a letter found by authorities who released only excerpts of it.

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Identifying the Soldier

Investigators identified the Tesla driver — who was burned beyond recognition — as Livelsberger by a tattoo and by comparing DNA from relatives. The cause of death was a self-inflicted gunshot to the head, according to coroner officials.

Authorities excerpted the messages from two letters Livelsberger wrote using a cellphone note application, Las Vegas Metropolitan Police Department Assistant Sheriff Dori Koren said.

The letters covered a range of topics including political grievances, domestic issues and societal issues, Koren said.

Tesla engineers, meanwhile, helped extract data from the Cybertruck for investigators, including Livelsberger’s path between charging stations from Colorado through New Mexico and Arizona and on to Las Vegas, Koren said.

“We still have a large volume of data to go through,” Koren said. “There’s thousands if not millions of videos and photos and documents and web history and all of those things that need to be analyzed.”

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Investigating the Motive

The new details came as investigators sought to determine Livelsberger’s motive, including whether he sought to make a political point with the Tesla and the hotel bearing the president-elect’s name.

Tesla CEO Elon Musk has recently become a member of Trump’s inner circle. Neither Trump nor Musk was in Las Vegas early Wednesday, the day of the explosion. Both had attended Trump’s New Year’s Eve party at his South Florida estate.

Investigators have not yet explained how Livelsberger shot himself inside the Cybertruck while simultaneously igniting fireworks and camp fuel packed inside, causing the explosion.

Investigators suspect Livelsberger may have been planning a more damaging attack, but the steel-sided vehicle absorbed much of the force from the crudely built explosive.

Among the charred items found inside were a handgun at Livelsberger’s feet, another firearm, fireworks, a passport, a military ID, credit cards, an iPhone and a smartwatch, Las Vegas Metropolitan Police Sheriff Kevin McMahill said. Authorities said both guns were purchased legally.

Personal Struggles and Military Service

A law enforcement official said investigators learned through interviews that he may have gotten into a fight with his wife shortly before he rented the Tesla in Colorado on Saturday and bought the guns. The official spoke on the condition of anonymity because they were not authorized to discuss the ongoing investigation.

In recent years Livelsberger confided to Alicia Arritt, a former girlfriend who had served as an Army nurse, that he faced significant pain and exhaustion she attributed to traumatic brain injury.

He opened up to Arritt, 39, whom he met and began dating in Colorado in 2018, about exhaustion, pain that kept him up at night, and reliving violence from his deployment in Afghanistan, Arritt said.

“My life has been a personal hell for the last year,” he told Arritt in text messages during their early days of dating that she shared with The Associated Press.

The Green Berets are highly trained U.S. Army special forces who specialize in guerrilla warfare and unconventional fighting tactics.

Livelsberger served in the Army since 2006. He rose through the ranks and deployed twice to Afghanistan and served in Ukraine, Tajikistan, Georgia and Congo, according to the Army. He recently returned from an overseas assignment in Germany and was on approved leave when he died, according to a U.S. official.

He was awarded five Bronze Stars, including one with a valor device for courage under fire, a combat infantry badge and an Army Commendation Medal with valor.

Authorities searched a townhouse in Livelsberger’s hometown of Colorado Springs Thursday as part of the investigation. Neighbors said the man who lived there had a wife and a baby.

Across-the-street neighbor Cindy Helwig said she last saw him when he asked to borrow a tool to fix an SUV.

“He was a normal guy,” said Helwig.

The truck explosion came hours after 42-year-old Shamsud-Din Bahar Jabbar rammed a truck into a crowd in New Orleans’ famed French Quarter early on New Year’s Day, killing at least 14 people before being shot to death by police. The FBI says they believe Jabbar acted alone and that it is being investigated as a terrorist attack.