 Cheadle will testify at a House hearing on Monday. Fox's Jonathan Serri reports from Butler, Pennsylvania. There's new video appearing to show 20-year-old Thomas Matthew Crooks lurking in the background of the rally about an hour before the gunfire erupted. Sources with knowledge of a closed briefing for senators say that was around the same time that law enforcement identified Crooks as a suspicious person. Crooks posted on a gaming website days before the shooting.