RICHFIELD — An Eagan man is accused of swindling at least $320,000 from his elderly mother and using the money to pay for a lavish lifestyle that included limousine services, phone sex and trips to spas and golf resorts.

Ward Allen Knutson, 46, told police his 86-year-old mother had given him permission to oversee her investments in 1999. Family members told authorities the mother at one point had assets worth between $3 million and $4 million.

The money didn’t last. Police said Doris Lavonne Knutson of Richfield was “essentially broke” in 2010, and that her accounts had been emptied “through mismanagement and theft.”

Ward Knutson was charged this month with felony swindling, a charge that carries a maximum sentence of 20 years in prison and a $100,000 fine. He declined comment.

He could face additional charges as well. Relatives have told police Knutson stole at least $65,000 from his incapacitated mother-in-law.

Hennepin County prosecutor Mike Freeman said financial abuse of seniors is a growing problem.

“Unfortunately we see too many of these where one of the kids starts to swindle their mother or father out of their estate,” Freeman said.

Over the years, Knutson reassured his mother she still had plenty of money. Family members recalled one conversation last year in which Doris Knutson asked how much her current balance was and Ward Knutson told her, “Probably over a million,” according to a Richfield police report.