SACRAMENTO, Calif. -- One condemned inmate killed another Friday, the first slaying of a death row inmate in California in more than 20 years, officials said.

Jonathan Fajardo, 30, was stabbed in the chest and neck with an inmate-made weapon. The stabbing took place in a recreational yard of the cell house that holds the bulk of condemned inmates at San Quentin State Prison, said corrections department spokeswoman Terry Thornton. Luis Rodriguez, 34, is considered the suspect, she said.

Investigators were trying to determine a motive and how the suspect obtained, or was able to make, the weapon, Thornton said.

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Such slayings are common in California prisons but rare on death row, where the last one occurred in 1997.

"It's very unusual," said San Francisco State University associate professor Amy Smith, who studies capital punishment and the psychological impacts of death row. "It's not supposed to happen, of course."

There is high security on death row, were every inmate is housed separately. Most are allowed to congregate in small groups in the exercise yard where Fajardo was killed, Thornton said.

Smith said that statistically, prisoners serving life sentences and "folks who are on 'the row' generally have the lowest levels of prison violence, even though it would seem that they might do anything because they have the worst penalty. In fact, they actually have very, very low incidences of violence in prison."

San Quentin State Prison is California's oldest prison. It opened in 1852 and houses 4,398 inmates, CBS SF Bay Area reports.

Fajardo was admitted from Los Angeles County in May 2011. He was awaiting execution on two counts of murder in the county in what was considered a hate crime. He also received seven life sentences.

Fajardo was identified as a Latino gang member who killed a 14-year-old black girl in a racially motivated shooting. He was also condemned for the stabbing death two weeks later of a man who prosecutors said was killed because fellow gang members believed he might be cooperating with police.

Rodriguez was admitted from Los Angeles County in August 2008. He is awaiting execution on two counts of murder. Local media reports identified Rodriguez as a member of another Latino gang convicted of killing two men from a rival gang. He was already suspected of another murder that resulted in a life sentence.

No one has been executed in California since 2006, though voters in 2016 passed an initiative that is attempting to speed up capital punishment. Far more condemned inmates on the nation's largest death row have died of natural causes or suicide than have been executed since California reinstated capital punishment in 1978.