The portrait pieced together so far of the 20-year-old nursing home aide who allegedly tried to assassinate Donald Trump at an election rally reveals frustratingly little about why he would make such an attempt — or how he managed to come so close to killing the former U.S. president.

The early details that have emerged about Thomas Matthew Crooks, who was shot dead by law enforcement, show a young man working an entry-level job near his hometown in Pennsylvania, where he graduated from high school in 2022 with a reputation as a bright but quiet classmate. His high school counselor described him as “respectful” and said he never knew Crooks to be political.

The FBI said on Sunday that Crooks’ social media profile does not contain threatening language, nor have they found any history of mental health issues. They said he acted alone and have not identified a motive.