HOUSTON (AP) A man sent to death row for the slaying of his ex-girlfriend's mother at her home in Austin six years ago has died in prison, Texas corrections officials said Wednesday.

Selwyn Davis, 30, was found unresponsive on the floor of his death row cell at the Polunsky Unit outside Livingston during a security check last Friday night, Texas Department of Criminal Justice spokesman Jason Clark said. When Davis couldn't be revived, he was taken to the prison infirmary and then to a hospital in Livingston where he was pronounced dead, Clark said.

The cause of Davis' death was not yet known. Autopsy results were pending and the prison agency's Office of Inspector General was investigating a standard procedure, according to Clark.

Davis was convicted and sentenced to death by a Travis County jury in 2007 for the fatal stabbing of 57-year-old Regina Lara during a burglary. His trial was marked by an obscene gesture he made to Lara's relatives while a probation officer testified about his criminal record.

He did not yet have an execution date.

According to trial testimony, Davis also sexually assaulted a teenage girl related to Lara. The 15-year-old girl showed up after school Aug. 22, 2006, to find Lara's cat missing and Davis in Lara's bedroom. She eventually would run to a nearby convenience store and call police.

Lara was strangled, had her skull fractured in a beating and was stabbed several times. The cat later was found wrapped in a pillowcase in a closet, and police said the stab wounds were consistent with the knife investigators determined was used to stab Lara.

Davis fled in Lara's van and was spotted in a store buying clothing to replace the bloody items he was wearing. He was arrested in another store where he was trying to buy some electronics.

In 2008, Davis' lawyer, Ariel Payan, said his client wanted to waive most of his appeals to accelerate the legal path to execution. Payan did not immediately return a phone call Wednesday from The Associated Press.

Two years ago, the Texas Court of Criminal Appeals upheld Davis' conviction and death sentence. There's no record of appeals for Davis in the federal courts.