A California Highway Patrol officer was slashed in the face with a sharp object early Tuesday in the town of Livingston during an encounter with a reportedly mentally ill man. The man was Tasered and taken into custody.

Raul Maldonado was booked into jail on attempted murder charges and is being held on more than $600,000 bail. Investigators say he ambushed a CHP officer after making prank 911 calls.

"What was told to me was he was making threats to the dispatchers or the call takers and kind of making sexual innuendos toward them and things like that," Sgt. Ray Fong of the Livingston Police Department told ABC30.

The suspect's grandmother let officers into the home, and they went into the 24-year-old's bedroom. That's when investigators say he ambushed one of them with a sharp object.

"A round was fired at this time," said Fong. "We don't know who fired the shot, but the subject was eventually subdued by Taser and taken into custody."

Authorities say the officer's bullet struck a cellphone or iPod in Maldonado's pocket, and only grazed his leg. He was treated, interviewed and booked into jail. Family members say they're upset that he was questioned because he's mentally ill and couldn't understand his Miranda rights. But police say it's standard procedure.