A decorated Army veteran who suffers from post-traumatic stress disorder called U.S. government leadership “weak” and appeared to admit that he intentionally blew up a Tesla Cybertruck outside the entrance to the Trump International Hotel in Las Vegas on New Year’s Day, the police said on Friday.

Deputy Sheriff Dori Koren of the Las Vegas Metropolitan Police Department said investigators were able to access one of two phones found in the Cybertruck and view writings on an app that appeared to serve as a diary documenting some of Matthew Alan Livelsberger’s movements and mental states from the date December 21st to New Year’s Eve.

Two letters in the phone app suggest a possible motive for the explosion, Koren said. In a letter, he tells “comrades, veterans and all Americans” that it is time to “wake up” because the country’s leadership is “weak” and “serves only to enrich itself.”

A second letter seemed to shed more light on Livelsberger’s thinking.

“We are the United States of America, the best country that has ever existed, but right now we are terminally ill and on the road to collapse,” a second letter said. “This was not a terrorist attack. It was a wake-up call. Americans only care about spectacle and violence. What better way to get my point across than a stunt involving fireworks and explosives? … I must cleanse my spirit of the brothers I have lost and free myself from the burden of the lives I have taken.”

Spencer Evans, special agent in charge of the FBI’s Las Vegas division, added that the investigation, along with an Army consultation, determined that Livelsberger likely suffered from post-traumatic stress disorder and that investigators were aware there were potential ” “family or personal problems” indicate grievances in his own life that may have contributed to this.”

Livelsberger expressed other complaints, including about conflicts elsewhere in the world and domestic political and social issues, Koren said. He warned that investigators would continue to comb through evidence found on the cellphone, and Las Vegas Sheriff Kevin McMahill said investigators had not been able to access a second phone found in the Cybertruck.

Evans said authorities had found no clear links between the Cybertruck explosion and the suspected terrorist attack in New Orleans hours earlier that killed 14 people on Bourbon Street.

The only connections investigators found appeared to be coincidental and coincidental, including the fact that both suspects rented their vehicles from the same company.

Livelsberger also harbored no animosity toward President-elect Donald Trump, Evans said.

Livelsberger was finally identified Thursday as the suspect behind the explosion, Las Vegas police said. The Clark County coroner determined he died of a self-inflicted gunshot wound, police said.

Authorities said they were able to identify Livelsberger’s badly burned body using a variety of methods, including family DNA and tattoos.

According to law enforcement officials, Livelsberger, 37, was on approved leave from the military when he rented a Tesla Cybertruck and drove from Colorado to Las Vegas. Firecrackers and gas in the back of that truck would later ignite after he parked it directly in front of the Trump Hotel entrance.

People who served Liverlsberger during his nearly two decades in uniform described him as a dedicated, patriotic soldier and a good teammate. Two soldiers who had served alongside him in recent years both expressed surprise at his behavior. One said he was “not a violent person.”

A soldier who served with Livelsberger said he often expressed his political views on social media and described most posts as “patriotic” and very pro-military, but added that this led to a clash with some fellow soldiers over theirs led to political differences.

“He posted a lot of political messages on social media that made some of us uncomfortable,” the person said. The soldiers requested that their names be withheld because they were not authorized to speak publicly about military personnel.

Alicia Arritt, a former girlfriend of Livelsberger, told NBC News that she dated him on and off for about three years. She said he was a proud soldier who also battled chronic pain, which she said he hid from his superiors.

She said he wasn’t particularly politically minded when she knew him and that she had lost touch with him over the past few years before suddenly receiving text messages from him in recent days. The messages said, among other things, that he had rented a Cybertruck, but there was no indication of what he was planning to do.

Livelsberger’s uncle Dean Livelsberger also told The Independent that Livelsberger was a very patriotic American who was an avid supporter of Trump. He did not immediately respond to an interview request from NBC News.

NBC News reviewed social media profiles that appeared to belong to Livelsberger and show a well-traveled man who recently had a child. Army officials said he first entered active duty in 2006, served in the National Guard and the Army Reserve, returned to active duty in December 2012 and was a U.S. Army special forces soldier.

Online, Livelsberger documented trips to Thailand and Italy on Tripadvisor and contributed photos to Google Maps showing food at a bar-bistro in San Juan, Puerto Rico, and a church in France, as well as a warning about a scam at a club in Puerto Rico Country of Georgia. He also posted about landmarks in Colorado, where he lived.

Additionally, Livelsberger had a relatively limited online presence, which included a LinkedIn page and a Facebook profile.

As part of his military career, Livelsberger was stationed in the Republic of Congo in 2014, Ukraine in 2016, Tajikistan in 2016 and Afghanistan in 2017, 2018 and 2019.

Public records show Livelsberger married in 2012 and later divorced in 2018. Records also show a marriage proposal filed in 2022. Also in 2022, a woman, Livelsberger, was apparently in a relationship, with pictures posted online showing her wearing a wedding ring.

In September, Livelsberger posted a photo on Facebook of himself and his partner cradling a newborn, and then a photo of himself holding the child while standing in front of a body of water. His right arm was covered in tattoos – tattoos later used by law enforcement to help identify his body after the Cybertruck explosion – that showed a recent addition to his tattoo sleeve near his right elbow: a triple crescent-shaped symbol three interlocking moons.

If you or someone you know is in crisis, call or text 988 to reach the Suicide and Crisis Lifeline or chat live on 988lifeline.org. You can also visit SpeakingOfSuicide.com/resources for additional support.