An inmate serving a life sentence for sexual assault killed a prison clerk and then committed suicide, authorities said Friday.

Rhonda Osborne, 33, was asphyxiated in the attack Thursday in a storage room at a maximum security prison unit, according to preliminary autopsy results released Friday by prison officials. Osborne had worked at the prison five years.

The attacker, Gary Laskowski (search), sentenced to life for two counts of aggravated sexual assault, later killed himself by cutting his neck and wrists with a sharp object, she said.

All of the evidence indicates a murder-suicide, but authorities continue to investigate, said John Moriarty, criminal justice department inspector general. Autopsies were pending.

Laskowski was working as a support service inmate, said Mike Viesca, a spokesman for the state corrections department. He had a clean disciplinary record and was a member of the general prison population. He entered the prison system in 1988, and had been at the Connally Unit for two years. He would have been eligible for parole in 2007.

The Connally Unit (search), which can house more than 2,800 inmates, was the site of the biggest prison break in state history in 2000 when seven inmates tricked and overpowered guards and civilian workers.

One escaped inmate killed himself rather than be captured, while the other six were eventually sentenced to death for the slaying of a police officer while they were at large.