The body of Diego Barajas Medina, 20, was found on Saturday morning by a maintenance worker in a bathroom at the Glenwood Caverns Adventure Park, in Colorado. The worker found him wearing body armour and tactical gear and armed with an AR-15 style rifle, a handgun and explosives.
His older brother, David Barajas Medina, 27, told NBC News that his brother was “a quiet person” who stayed up until 6am playing Call of Duty every night.
The 20-year-old was reportedly carrying ghost guns, which have no serial numbers and thus cannot be traced. He wore clothing bearing patches similar to law enforcement, and carried some fake explosives — like faux hand grenades — among his real ordinance.
“He always wanted to be a police officer, so he had guns. He had a vest,” Mr Medina told NBC.
But he added that he did not think his brother was “a dangerous person”. "I’m not sure what he was setting out to do," he said.
Mr Medina said his brother lost his last job at Family Dollar about a year ago and was flipping items on Amazon to make ends meet, though he had not kept up with the rent. He suggested that his brother may have been depressed.
When police searched Medina’s vehicle, they found multiple improvised explosive devices. No other explosives were found throughout the park.
Garfield County Sheriff Lou Vallario said that the 20-year-old was “completely under the radar” and that he could have done “tremendous damage” to the park and its visitors.
"Given the preparation, given the amount of weapons and ordinance he had, it almost seemed very highly likely he intended to use those against the community. He chose not to," Mr Vallario told the press.
Medina had no criminal history and no known previous encounters with law enforcement, according to the Associated Press.
“We don’t see any history, we don’t see any reason, we don’t see any motive. He was just completely under the radar,” Mr Vallario said. “To the best of my knowledge at this point … there was nothing to indicate any type of warning, or any type of concern on the part of family, friends, school, what have you.”
Mr Vallario said that a note was written on the wall of the women’s bathroom — where the man’s body was located — but that he could not be certain that the message was left by Medina.
The incident comes amid the ongoing fallout from a mass shooting in Lewiston, Maine, last week, in which 18 people were killed and 13 more were injured.