DENVER (KDVR) The FBI said that in the months leading up to the shooting at a high school in Colorado, the agency had been looking into a social media account that discussed planning a similar attack.

On Monday, affiliate KDVR asked the FBI if it had received a tip this summer related to the shooter. In a response, the agency said it had been looking into an account that shared non-specific threats about planning a mass shooting. The agency said it had not identified the person behind the account as of the day of the Evergreen shooting.

“In July 2025, the FBI opened an assessment into a social media account user whose identity was unknown and who was discussing the planning of a mass shooting with threats non-specific in nature,” the agency said.

On Sept. 10, a 16-year-old student shot two other students and himself at the school. The shooter died of a self-inflicted gunshot wound at a hospital that evening, and one of the two victims has since been identified.

On Friday, the Anti-Defamation League released a report showing what it says was online activity from the shooter. The organization found that he had posted tributes to other mass shooters, including a homemade T-shirt replicating one worn by one of the Columbine High School shooters.

“The ADL Center on Extremism regularly shares alerts and updates with law enforcement. We shared profiles and activity at the time with law enforcement for actions they deemed necessary based on what was available at the time. We have since learned those profiles belonged to the individual responsible for the shooting in Evergreen,” said Oren Segal, the ADL’s senior vice president of Counter-Extremism and Intelligence. “We do not share alerts to law enforcement outside of law enforcement and there is a current investigation.”  

The FBI said its work looking into the social media account that had posted threats continued up until the day of the shooting.

“We continued to work this assessment investigation to identify the name and location of the user up and until September 10, 2025. During the assessment investigation, the identity of the account user remained unknown, and thus there was no probable cause for arrest or additional law enforcement action at the federal level,” the FBI told FOX31.

James Allbe, a law enforcement procedural expert, said the Evergreen High School shooting case highlights a pattern of missed warning signs.

“It’s almost appalling that we’ve got all of this intel, and yet you and I are sitting here having to have this conversation again after another school shooting,” Allbee said Monday.

Allbee said an FBI assessment begins when concerning activity is located online. He said that vague social media posts that investigators saw lacked the specifics required for immediate action.

“An assessment can start in several different ways—algorithms, key words that trigger concern, or task forces actively scrolling these websites,” Allbee said. “A credible threat in my eyes is when someone says, ‘On this date, at this time, I’m going to take action.’ Those kinds of threats are much easier to jump on.”

Allbee said that the FBI must sift through an enormous volume of similar tips.

“The FBI gets hundreds of complaints every month, if not every week or even daily, and they just don’t have the resources to act on all of them as quickly as they’d like,” Allbee explained.

However, Allbee questioned why more aggressive steps were not taken sooner.

“Law enforcement has so many resources that could have been used to find this individual. I don’t know why that wasn’t done,” Allbee told Powers. “They should have obtained this information and gotten it over to the Jefferson County Sheriff’s Office.”

The Jefferson County Sheriff’s Office said during a press conference last week that the shooter was “radicalized through an extremist network” and would share further details about that later.

“There’s some level of confirmation that there’s something we really need to take a deeper look at,” the spokesperson said.

The Anti-Defamation League said that immersion in graphically violent online communities can desensitize young people to violent acts.