INDIANAPOLIS (AP) — The cellphone of a 20-year-old man who fatally shot three people last year at an Indianapolis-area mall contained photos of Adolf Hitler, Nazi propaganda, firearms and “extremely graphic" videos of previous mass killings, police said Thursday.

Police said the FBI found nothing on the phone about the mall or plans for last year’s mass shooting, but it contained what appeared to be a suicide note Jonathan Douglas Sapirman had written more than two years before the attack.

Greenwood police said the FBI was able in May to unlock the phone, which Sapirman dropped into a mall toilet before he opened fire inside the food court of Greenwood Park Mall last July 17. Sapirman was fatally shot by an armed shopper shortly after the shooting began in the city just south of Indianapolis.

Police said the FBI recovered more 200 videos and more 3,400 images from the phone, along with notes kept on the device, call and text logs and internet searches. Many of the videos were of mass shootings and “extremely graphic in nature,” including one of a September 2016 attack that killed five people at Cascade Mall in Burlington, Washington.

The FBI also found photos of Adolf Hitler and Nazi propaganda on the cellphone. The FBI's findings come after police said in December that Sapirman was fascinated with Nazi Germany and had also posted more than 700 comments on social media about mass killers between 2017 and 2022.

Police said “the most notable discovery” on the phone was a photo of a handwritten note taken on April 9 2020, which appeared to be a suicide note written by Sapirman.

That note begins with, “My final thoughts on paper" and goes on to say, “I’m a sociopath. I want to hurt people.” Police said the note alludes to Sapirman shooting himself with a shotgun, with the explanation that “This was the result of my issues: mental instability, depression, frustration, and sexual isolation.”

Police said that Sapirman's apparent suicide note more than two years before the shooting "leads us to believe that Sapirman's "homicidal and suicidal thoughts had been manifesting for years.”

Sapirman's ex-girlfriend had told investigators that he told her he didn’t expect to make it to age 21 and that if he killed himself, he would “take others” with him, police said in December.

Also found on the phone was a note written less than a month before the shootings that was apparently a draft of a text Sapirman intended to send his brother. In that June 18, 2022, note he wrote, “I'm gonna shoot myself" and later the same day he conducted an internet search for “how to go through with committing suicide,” police said.

Police previously said that data on Sapirman’s laptop was destroyed after he placed it in an oven set on a high temperature with a butane tank before the shooting, but that the FBI was working to determine the phone’s password — a process that could take years.

While the three slain victims were Hispanic, Greenwood Police Chief James Ison said in December that there was no indication the shooting was racially motivated and authorities had not determined a specific motive for the attack. The shooting killed married couple Pedro Pineda, 56, and Rosa Mirian Rivera de Pineda, 37; and Victor Gomez, 30.

However, Ison said previously that Sapirman's ex-girlfriend told investigators he was racist toward African Americans and Hispanics because of “bad experiences that he had with people in those races while he was growing up.”

An armed bystander, 22-year-old Elisjsha Dicken of Seymour, Indiana — who had been at the mall shopping with his girlfriend — fatally shot Sapirman after police say the gunman fired 24 times within 15 seconds.

Police have praised Dicken, who was legally armed, for his quick actions that ended the shooting attack, with Ison calling him “a true hero."