The CEOs of several major online social platforms have been invited to testify before Congress about the potential for radicalization on online forums following the killing of conservative commentator Charlie Kirk.James Comer, chairman of the House Oversight and Government Reform Committee, invited the heads of Discord, Steam, Twitch, and Reddit to testify after authorities revealed that Tyler Robinson, the 22-year-old suspected of killing Kirk, was said to have been influenced by the “dark corners of the internet.” The oversight committee said it would examine the “radicalization of online forum users, including instances of open incitement to commit politically motivated acts,” on specific platforms, according to a congressional press release. Read More: The Killing of Charlie Kirk and the Political Violence Haunting America“The politically motivated assassination of Charlie Kirk claimed the life of a husband, father, and American patriot. In the wake of this tragedy, and amid other acts of politically motivated violence, Congress has a duty to oversee the online platforms that radicals have used to advance political violence,” said Rep. Comer, a Republican from Kentucky.The FBI is currently investigating the involvement of “a lot more” than 20 users who participated in a Discord chat with Robinson before Kirk’s shooting, according to FBI Director Kash Patel, who spoke in front of the Senate Judiciary Committee on Tuesday. Utah Governor Spencer Cox said over the weekend that Robinson’s friends had told investigators that he was involved in “dark places” of the internet and “Reddit culture,” which was indicated by obscure messages inscribed on bullet casings recovered by authorities. Robinson, it was revealed in texts to his partner, inscribed those messages on the casings as one “big meme.”The messages contained references to online gamer culture that only a select audience would have understood. One read: “Hey fascist! CATCH! (up arrow symbol, right arrow symbol, and three down arrow symbols)”. Those words were likely a reference to a sequence of moves on a controller that unleashes a powerful bomb and accompanying phrase in a third-person shooter video game called Helldivers 2. The phrase has morphed into a meme that is commonly used on message boards to signal an end to a conversation.Robinson appears to have been a frequent user of Discord, an instant messaging app and social platform popular with gamers and content creators. Messages said to be from Robinson show him admitting to killing Kirk on a Discord chat, according to a source who showed messages to the Washington Post. “Hey guys, I have bad news for you all,” a user in the chat that was allegedly Robinson said, according to the Post. “It was me at UVU yesterday. im sorry for all of this.”The most revealing messages about Robinson’s motive were in a text exchange between him and his partner, where investigators said he confessed to the crime and said that he had “had enough of his hatred,” in reference to Kirk. “Some hate can’t be negotiated out,” Robinson texted his partner, prosecutors announced on Tuesday.Deputy Director of the FBI Dan Bongino said that Robinson had an “obsession” with Kirk based on his digital footprint and said the shooting was “clearly” an “ideologically motivated attack” in an interview on Fox on Monday.Discord, which was originally intended for gamers, has been documented to have bred extremist rhetoric in the past.