SAN QUENTIN (CBS13) – A San Quentin State Prison inmate on death row was declared dead after being found unresponsive in his cell Thursday morning, the California Department of Corrections and Rehabilitation.

Lumord Johnson, 56, was pronounced dead at 6:55 a.m. and his cause of death is being investigated by the Marin County Coroner’s Office.

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According to the CDCR, Johnson was sentenced to death in Riverside County on April 8, 2002.

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He was convicted of first-degree murder with enhancements for being armed with a firearm and the use of a firearm and a consecutive life-with-the-possibility-of-parole sentence for second-degree murder with an enhancement for use of a firearm, officials said.

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Johnson was admitted to death row two weeks later.