Jan. 13 (UPI) -- The man who killed 58 people and wounded more than 500 others this fall on the Las Vegas Strip took elaborate steps to avoid being detected by authorities, newly released documents show.
On Friday, U.S. District Judge Jennifer Dorsey unsealed more than 300 pages of documents filed by the FBI after the shooting. The Las Vegas Review Journal and CNN were among the media outlets filing suit for the documents' unsealing.
From a 32-floor hotel room at the Mandalay Bay Resort and Casino, Stephen Paddock opened fire on people attending a country music festival. Authorities say he left a note before he killed himself but no motive has been revealed.
The documents detail how he attempted to thwart authorities.
One warrant described how he "destroyed or tried to hide digital media devices."
Paddock used anonymous communications devices, including a prepaid cellphone. He had a "level of sophistication which is commonly found in mass casualty events," investigators said.
"Paddock planned the attack meticulously and took many methodical steps to avoid detection of his plot and to thwart the eventual law enforcement investigation that would follow," the FBI said.
Three cellphones were found in his room at Mandalay Bay, including two that investigators searched and one that they could not unlock.
According to the FBI, hundreds of rounds of spent ammunition as well as "preloaded high-capacity magazines," were found in suitcases that Paddock had brought to the room. Also found were body armor, range finders and a homemade gas mask.
Paddock bought many of the items on the Internet during the 12 months leading up to the attack.
He spent "significant time and expense prior to the attack purchasing and caching weapons" and other items, such as glass cutters and suitcases, according to documents. The glass cutters were used to cut the windows of the hotel.
Paddock's girlfriend, Marilou Danely, told investigators that her fingerprints would likely be found on Paddock's ammunition because she "occasionally participated in loading magazines."
She has adamantly denied any advance knowledge of the attack, according to the court records.
Danely was cooperating with investigators and that the investigation "to date has not produced any conclusive evidence that Danely aided Paddock, had foreknowledge of his plans, or has been deceptive with law enforcement," according to the documents.
Within hours after the massacre, she deleted her Facebook account, according to search warrants. She had set her Facebook account to private and later deleted the account. Hours later, authorities located her in the Philippines and identified her as "a person of interest" in the shooting.