Well, there is no way to tell if someone is going to become a murderer. Aaron Hernandez despite some issues in his past had a clean record. Who'd predict he'd become an 'alleged' executioner.

"Hernandez "drove the victim to the remote spot, and then he orchestrated his execution," a prosecutor said in a Massachusetts courtroom Wednesday.
"He orchestrated the crime from the beginning and took steps to conceal and destroy evidence," the prosecutor said.