 We don't know his opinions or affiliations. I'm standing in front of the accused shooter's home, surrounded by police tape. Authorities believe he acted alone. Fox's Jonathan Seri in Bethel Park, Pennsylvania. 20-year-old Thomas Matthew Crooks was not on law enforcement's radar. No social media rants that they could find. Investigators have yet to determine a motive. They're unaware of any ideology he might have had.