California prison officials say two inmates attacked and killed another prisoner Wednesday afternoon at Kern Valley State Prison in Delano.

The California Department of Corrections and Rehabilitation says Timothy Whelan, 56, was killed Wednesday afternoon.

William Nesler III, 43, and Edward Holden III, 35, allegedly attacked Whelan with improvised weapons.

Whelan was serving a sentence of life with the possibility of parole for an illegal firearms conviction in Los Angeles County in 2005.

Nesler and Holder are both serving life sentences.

Prison officials and the Kern County District Attorney’s Office are investigating the murder.