BOULDER, Colo. - A man who stole $578,000 from his 94-year-old mother-in-law, who suffers from dementia, has been sentenced to six years in prison.

The Daily Camera reports 63-year-old John Charles Byrne was sentenced Friday in Boulder on felony and misdemeanor theft charges. Byrne, who now lives in Arizona, was appointed trustee and fiduciary for his mother-in-law, Charlotte Irey Short, in 2005. Soon after, he listed himself as Short's dependent, citing back problems as a health matter.

Byrne had been married to Short's only daughter, who died at age 30, before he re-married.

Court records say he drained Short's liquid assets to support himself and his family -- spending money on trips to Mexico and hotels. He also was accused of investing heavily in a Ponzi scheme.

Byrne must pay $912,550 in restitution.