New details emerge about 20-year-old shooter [Video]

WASHINGTON — The 20-year-old nursing-home employee from suburban Pittsburgh who tried to assassinate former President Donald Trump was a registered Republican who packed explosives in the vehicle he drove to the campaign rally an hour from his home.

Law enforcement officials were working Sunday to learn more about Thomas Matthew Crooks of Bethel Park, Pennsylvania, to determine what motivated him to open fire on the rally from a nearby rooftop, killing one spectator, before he was shot dead by the Secret Service.

The FBI said Sunday it has not yet identified any threatening writing or social media posts from Crooks, who graduated from high school two years ago and had no past criminal cases against him, according to public court records. The FBI believes he acted alone.

Trump, the presumptive Republican presidential nominee, said on social media the upper part of his right ear was …