LOS ANGELES, United States, Jan 4, 2025 (BSS/AFP) - The decorated Green Beret who died by suicide in a blazing Cybertruck outside a Trump hotel in Las Vegas was suffering from post-traumatic stress, investigators said Friday, saying they had found no links to "terrorist" groups.

Matthew Livelsberger, 37, a member of the elite US special forces, shot himself on New Year's Day in the rented Tesla vehicle filled with fuel containers and fireworks, which exploded.

Seven people nearby in the valet area of the glass-fronted Trump International Hotel were wounded in the blast.

"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 Spencer Evans told a press conference on Friday.

Investigators said they were still examining Livelsberger's devices, but that so far they had found two letters on his phone in which he spoke of the "burden" of having taken lives, among other issues.

Though the truck exploded outside the Trump-branded hotel in Las Vegas, part-owned by US President-elect Donald Trump's family business, Livelsberger "held no animosity" towards the Republican, Evans said.

And he said investigators have "not identified any connection between this subject and any other terrorist organization."

He said some personal and family issues may have contributed to the incident.

Livelsberger's body was burned beyond recognition, but Las Vegas Sheriff Kevin McMahill said authorities had confirmed via dental records and DNA that he was indeed the person who died inside the Cybertruck.

He said investigators were still working to establish the exact sequence of events in the Cybertruck, but for now it appeared that Livelsberger shooting himself dead and the blast which ignited the truck were "simultaneous."

Evans also said again that investigators have found no link between the blast and the deadly attack in New Orleans which also took place on January 1.

In that attack, a US army veteran loyal to the Islamic State jihadist group rammed a crowd of New Year's revelers with a truck, killing 14 before being shot dead by police.