A Houston man prosecutors accuse of trying to kill Judge Julie Kocurek is facing additional federal charges after officials say he tried to reach out to witnesses from behind bars.

Chimene Onyeri is charged with six counts of witness tampering, according to a newly amended federal indictment. Prosecutors say he passed notes to a fellow inmate at the Travis County Jail with instructions to call six people to try to tell them not to talk to law enforcement.

The indictment identifies the witnesses only by their initials, and it is unclear how federal investigators learned about the notes.

Chimene Onyeri

Onyeri is accused of trying to kill Kocurek in November 2015 outside her West Austin home by firing several rounds into a car in which she was riding.

Two other men, Marcellus Burgin and Rasul Scott, also are accused of being part of the attack and working with Onyeri as part of an organized ring that also involved financial crimes. A judge has set a trial date for October.

Kocurek was severely injured and is recovering from the attack. She has since returned to the bench.