The man convicted of killing Kristin Smart has been hospitalized after an attack at a California state prison where he had been housed for only five days, his attorney said Thursday.

Paul Flores was convicted of Smart's murder in October, more than 25 years after she vanished from the California Polytechnic State University campus. Her body was never found, but a true crime podcast reignited interest in the cold case, leading prosecutors to charge Flores with killing Smart during a rape or attempted rape.

Flores' attorney, Harold Mesick, told USA TODAY that he was notified of the attack on Wednesday, though he didn't provide further details, including where his client was hospitalized.

The California Department of Corrections and Rehabilitation confirmed that Flores was taken from Pleasant Valley State Prison to a medical facility for injuries that left him in serious condition.

He was in fair condition on Thursday morning, the agency said.

The circumstances of the attack are under investigation and no other details were immediately released.

Mesick said that if Flores' condition continues to improve, the corrections department will decide whether he will return to the prison under protective custody.

Who was Kristin Smart?

Kristin Smart was an adventurous and ambitious 19-year-old freshman of communication studies at California Polytechnic State University in San Luis Obispo, according to her loved ones. She dreamed of traveling the world before she disappeared without a trace while walking back to her dorm room one night in 1996.

Witnesses say that she got drunk at a party about a 10-minute walk from her dorm room. Two students decided to walk her back to her dorm, and Paul Flores offered to join them.

He was the last one with her before she disappeared. Her body was never found.

In 2019, she became the subject of a true crime podcast investigation on "Your Own Backyard," providing new leads to help build the case against Flores.

How did they catch Kristin Smart's killer?

The podcast helped to bring forward new witnesses, but police also had collected evidence in the months after her disappearance. Here are some of the public details that were released ahead of the trial:

• Paul Flores was the last person to see her alive. Four other women had accused Flores of drugging and raping them in the past. Prosecutors had a video that Flores had recorded of himself raping a drunk woman in Southern California.
• Flores had a black eye the week of Smart's disappearance, with conflicting stories on how he got it.
• Sheriff's didn't search Flores' room until it was cleared out for the summer. But four separate cadaver dogs alerted in his room and no one else's.
• Prosecutors said traces of human blood were found under a deck behind Paul Flores' father's home. That's where they believe her body was buried before being moved to another location. 

How long has Paul Flores been in prison?

A California judge sentenced Paul Flores to 25 years to life in prison in March, calling him "a cancer to society."

Flores had only been at Pleasant Valley State Prison for about five days, Mesick said. It was likely to be his permanent residence after initially living at the North Kern State Prison, which Mesick called a classification prison.