Transcript for Dayton shooting suspect was exploring violent ideologies: FBI
Late today what the FBI revealed there, saying the shooter might have been motivated by violent S. The chaos and terror inside that bar. And tonight, right here, the new clues revealed about the gunman, as we hear from a former girlfriend who said herself there were red flags. What he was fascinated with. ABC's Eva pilgrim leads us off from Dayton tonight. Reporter: Tonight, stories from heroism from inside the Dayton bar where the gunman's rampage ended. Dylan Arnold was about to leave when the shooter rushed the door. He says the bouncer, seen here crouched by the door, saved lives. You can see him here alerting staff as the shooter rushes toward the bar. If he wasn't there, and especially if the officers weren't there, I mean, I know I'd be gone, one of the first Reporter: As authorities search for a motive, the FBI now investigating evidence they say shows Connor BETTs was exploring violent id yojs. He had expressed a desire to commit a mass shooting. Reporter: Just this past may, Adelia Johnson, who says she was dating BETTs, broke it off, after what she calls several red He talked about mass shootings and world tragedies like I talk about television shows. Reporter: ABC news has else learned of a now deleted Twitter account believed to be linked to BETTs, describing himself as a an any may fan, a methead and a leftist. In less than 30 seconds, dozens were hurt. Nine people killed. 25-year-old Nick hummer spent the summer working with cancer patients. He'd just been offered his dream He's going to leave a big hole in our organization, for sure. I think he's left a hole in our hearts. Do something! Reporter: Ohio's governor who was drowned out by a crowd in the wake of the shooting, now says he's calling for legislation requiring background checks for nearly all gun sales and other reforms. We must do something. And that is exactly what we are going to do. And Eva pilgrim joins us live from Dayton, Ohio. And the FBI revealing today they have evidence now that the gunman was interested in violent ideologies, and they're asking now for the public's help? Reporter: That's right, the gunman is investigating if this shooter had any help. They want to talk to anyone who might have known that he was interested in mass shootings. Now, if you had video of this shooting, the FBI would like for you to submit that on their website. David? It does seem like there were so many red flags here. Eva pilgrim leading us off.
This transcript has been automatically generated and may not be 100% accurate.