Investigators are examining the teen’s possible ties to groups the FBI describes as “nihilist violent extremists,” as well as whether anyone online encouraged or helped plan the attack. People familiar with the investigation said authorities have not confirmed that there were any co-conspirators.

Law enforcement has sought information from Discord and other online platforms through legal requests, according to sources familiar with the case. Discord is a gaming and chat service. Investigators are also working to determine the shooter’s motive and how he obtained the shotgun used in the attack.

One group under investigation is 764, a decentralized online network that the FBI says glorifies violence, mass killers and self-harm. Authorities have described the group as seeking to spread chaos. It operates across online platforms, including Discord, according to law enforcement sources and court records.

The investigation remains in its early stages, and officials have not publicly described what evidence they have collected. Four people familiar with the inquiry, including law enforcement officials, spoke anonymously because the investigation is ongoing. The FBI and U.S. Department of Justice did not respond to questions, while the Deschutes County District Attorney’s Office declined to comment. Bend police did not immediately respond.

The Bend investigation follows a separate Oregon case in which Multnomah County authorities linked 764 to an inquiry into a Benson High School student who released toxic chemicals in a cafeteria earlier this month.

Researchers say online spaces that glorify violence can draw in socially isolated young people, and some communities use coercion or exploitation. James Densley, a criminology professor and co-founder of the Violence Prevention Project Research Center at Hamline University, said participation can range from consuming violent content to actively contributing to it. He also warned that some online groups exploit young people.

Separately, the Oregon Department of Justice is investigating whether Discord failed to protect minors on its platform. On Monday, the agency sent the company a civil demand for information about teen accounts dating to 2021.

Attorney General Dan Rayfield said the state’s inquiry is part of a broader examination of social media and artificial intelligence technologies that can harm children. He called for stronger oversight and accountability if companies put young users at risk.