Federal prosecutors have decided to not pursue criminal charges against three Fullerton police officers whose violent encounter with Kelly Thomas five years ago resulted in the homeless, mentally ill man’s death.

Department of Justice officials said Monday that prosecutors have determined that they are unable to prove that former officers Manuel Ramos, Jay Cicinelli and Joseph Wolfe violated Thomas’ civil rights.

The now-closed federal civil rights case was the last remaining investigation into 37-year-old Thomas’ death, which drew national attention after security video of his deadly encounter with police at the Fullerton Transportation Center went viral.

Thomas’ father, Ron Thomas, said he wasn’t surprised by the Department of Justice’s decision, given how long the investigation has lasted.

“I didn’t have much faith in it at all,” Ron Thomas said Monday of the federal investigation. “But that is over with now, and I’m moving forward and will continue with my advocacy work.”

Read the rest at the Orange County Register.