Authorities say they can't comment on what caused the injury, but Sheriff Mark Pazin says it happened before Romero was booked into jail on murder charges. He's been on suicide watch ever since.
"There have been indicators that he would do harm to himself. And regardless of how we view this situation regarding his wife, we are still in charge of ensuring all the inmates are safe regardless of what the allegations are," Sheriff Pazin said.
Action news has learned Romero did injure himself while being treated for stab wounds at a Modesto hospital.
He was taken there last Thursday morning after police found the former school bus driver in critical condition in his backyard. That's also where they found his wife, elementary school teacher Diane Romero, dead. Rudy is now being kept in a safety cell.
"The cell that inmate Romero is in right now is basically a mirrored hard glass cell wherein our correctional officers can view him on a continuous basis so he doesn't do any harm to himself," Sheriff Pazin said.
Family members of both Rudy and Diane Romero attended Friday's court hearing, but did not want to comment on the case.
The judge ultimately granted the public defender's request for more time before entering a plea. Rudy Romero's bail remains at $1 million.