In short:
Investigators say the man who died in a Tesla Cybertruck outside a Trump hotel in Las Vegas, left a note saying the stunt was a "wake-up call" for the country's ills.
Matthew Livelsberger, 37, also wrote on 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".
What's next?
Pentagon officials have declined to say whether whether the US Army Green Beret may have been suffering from mental health issues but say they have turned over his medical records to police.
Investigators say the US Army soldier who died in an explosion of a Tesla Cybertruck at the Trump hotel in Las Vegas left a note saying it was stunt to serve as "wake-up call" for the country's ills.
Matthew Livelsberger, a 37-year-old Green Beret from Colorado Springs, 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 harboured no ill will toward president-elect Donald Trump, Clark County sheriff's 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.
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The explosion caused minor injuries to seven people but virtually no damage to the hotel.
"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.
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 coroners officials.
What we know about the man accused of the Tesla Cybertruck explosion
Photo shows A burnt ID document featuring the photo of Matthew Livelsberger
Pentagon officials have declined to say whether Livelsberger may have been suffering from mental health issues but say they have turned over his medical records to police.
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 Mr Musk was in Las Vegas on the day of the explosion.
Both had attended Trump's New Year's Eve party at his South Florida estate.
Elon Musk and his son attended a New Year's Eve event held by Donald Trump at Mar-a-Lago in Palm Beach, Florida. (Reuters: Marco Bello)
Investigators said previously that Livelsberger shot himself in the head inside the truck packed with fireworks just before it exploded outside Trump International Hotel in Las Vegas on New Year's Day.
"It's not lost on us that it's in front of the Trump building, that it's a Tesla vehicle, but we don't have information at this point that definitively tells us or suggests it was because of this particular ideology," Mr Evans said on Thursday at a news conference.
When asked on Friday, local time, about whether Livelsberger had been struggling with any mental health issues that may have prompted his suicide, Pentagon spokeswoman Sabrina Singh told reporters that "the department has turned over all medical records to local law enforcement".
A law enforcement official said investigators learned through interviews that he may have gotten into a fight with his wife about relationship issues shortly before he rented the Tesla on Saturday and bought the guns.
The official spoke on the condition of anonymity because they were not authorised to discuss the ongoing investigation.
The Las Vegas Police Department shows an ID document belonging to Matthew Livelsberger that was found in the Cybertruck. (AP: Las Vegas Police Department)
Authorities are still working to determine a motive.
Among the charred items found inside the truck were a handgun at Livelsberger's feet, another firearm, fireworks, a passport, a military ID, credit cards, an iPhone and a smart watch, Clark County Sheriff Kevin McMahil said.
Authorities said both guns were purchased legally.
Livelsberger had served in the army since 2006, rising through the ranks with a long career of overseas assignments, deploying twice to Afghanistan and serving in Ukraine, Tajikistan, Georgia and Congo, the army said.
He had recently returned from an overseas assignment in Germany and was on approved leave when he died, according to a US official.
He was awarded a total of five Bronze Stars, including one with a valour device for courage under fire, a combat infantry badge and an Army Commendation Medal with valour.
Authorities searched a townhouse in Livelsberger's hometown on Thursday as part of the investigation. Neighbours said the man who lived there had a wife and a baby.
FBI Deputy Assistant Director Chris Raia said on Thursday, that officials have found no "no definitive link" between an attack in New Orleans, where another US Army veteran drove a truck into a crowd of people, killing at least 14 and the truck explosion in Las Vegas.
AP