The leader of the white supremacist group Republic of Florida told the Anti-Defamation League on Thursday that Nicolas Cruz, responsible for a shooting spree at a Florida high school that killed at least 17 people on Wednesday, trained with the organization and belonged as a part-time member.

Cruz, a former student at Marjory Stoneman Douglas High School in Parkland, Florida, allegedly opened fire with an AR-15 rifle on the grounds until killing or wounding dozens of students and teachers. The domestic terrorist has been taken into custody and charged with premeditated murder.

4chan, an online forum with a heavy concentration of alt-right users, hosted discussions of Cruz’s involvement with the group in 2017 and early 2018. Self-described Republic of Florida members claimed on 4chan that Cruz was an active member of the “ROF” in 2017.

The ROF member who spoke to the ADL identified himself as Jordan Jereb. Jereb claimed that Cruz had participated in militaristic training with the white nationalist organization one or multiple times.

Late on Wednesday, The Daily Beast reported that students who had attended Douglas High with Cruz said that the killer often wore President Trump hats and ranted about Muslim terrorists, feuding with teachers and other teens. “Most kids ignored him at school. They pushed him off to the side as if he was garbage. He screamed in class one time,” 17-year-old student Ocean Parodie told the website. “He was definitely not accepted at our school socially.”