An inmate convicted of the gruesome 1991 kidnapping and murder of a mid-Missouri convenience store clerk has died in prison.

Convicted killer Marvin Chaney (2013 photo courtesy of the Missouri Department of Corrections)

The Missouri Department of Corrections (DOC) says 56-year-old Marvin Chaney died Tuesday morning of “apparent natural causes” at the maximum-security Potosi Correctional Center in Mineral Point.

Chaney has been in prison since April 1997. He was serving a life sentence, without the possibility of parole.

Chaney and another man, Jess Rush, were both convicted of first degree murder and kidnapping for the death of Trudy Darby on January 19, 1991.

Darby was abducted from the Macks Creek K&D convenience store during the late-night hours. Macks Creek is in Camden County.

Court records indicate Darby was shot twice in the head.

Her body was later found near the Little Niangua River.

Rush is currently incarcerated at the South Central Correctional Center in Licking.