PLEASANT HILL (CBS / AP) — An at-home caretaker convicted of killing her 70-year-old client is headed to prison for 31 years to life in prison.

A Contra Costa County judge gave Diane Warrick the maximum term for the second-degree murder. During Thursday’s sentencing, Judge Leslie Landau said “this defendant is one of the most dangerous I’ve seen.”

READ MORE: Former Oakland Police Captain Wounded During Fatal Shooting At Gas Station

Prosecutors say retired social worker Mary Jane Scanlon hired Warrick through a Craigslist ad, unaware that the woman had a criminal past. She was convicted of robbing a Colorado pharmacy in 1988, then committed to a mental hospital for four years after taking hostages and shooting at police at a Napa pharmacy in 1997.

READ MORE: Storm System Brings Hope to Parched North Bay, Reservoirs

Last June, Warrick repeatedly stabbed the 85-pound Pleasant Hill woman in her bed. She testified at trial that she was hallucinating about attacking her father at the time.

MORE NEWS: Alameda County Fair Makes Return In Fall After Pandemic Hiatus

(Copyright 2011 by CBS San Francisco. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. Wire services may have contributed to this report.)