A prosecutor says an Ohio prison inmate was strangled while riding in a transport van with other prisoners and guards inside.

Ross County Prosecutor Matthew Schmidt says guards on the vans apparently cannot see the inmates.

He says the van was leaving Columbus and headed back to the Ross County Correctional Institution in Chillicothe when the Wednesday afternoon slaying happened.

Schmidt says the slain inmate had been taken to Columbus for medical treatment.

The Ross County Coroner's Office on Monday identified the slain inmate as 61-year-old David Johnson. Prison records say he was serving an eight-year sentence for sexual battery out of Franklin County.

The Department of Rehabilitation and Correction declined to comment and referred questions to the state patrol.