SANTA ANA, Calif. » A man who killed a Southern California casino winner during a botched robbery has been sentenced to 25 years to life in prison.

The Orange County Register says Tad Carroll was sentenced Friday, two months after pleading guilty to first-degree murder.

Another defendant, Barbara Hamel, had pleaded guilty to second-degree murder but prosecutors say she backed out of a plea deal Friday and the case will return to court.

Orange County prosecutors say the pair followed 55-year-old Chi Bui after he won $10,000 at the Hawaiian Gardens Casino in Los Angeles County in 2010.

Bui was confronted in Santa Ana.

Prosecutors say Carroll knocked him down and Hamel drove over his head, killing him instantly.

A third defendant, Michael Ross of Long Beach, received a 15-years-to-life sentence last year.