A mother and son accused of running a prostitution ring that operated brothels in Rohnert Park and Santa Rosa pleaded no contest to criminal charges that could send one to prison for up to 16 years, prosecutors said Thursday.

“This was a very well-organized business established over several years that profited by sexually exploiting young women. We believe the pleas entered are appropriate and reflect the seriousness of the offenses,” District Attorney Jill Ravitch said in a statement.

David Romesburg entered no-contest pleas to felony charges of money laundering, pimping and pandering, the District Attorney’s Office said in a press release. He also admitted to having been previously convicted of statutory rape in 1999, a strike offense under the state’s three-strikes law.

He faces up to 16 years in prison when he is sentenced Oct. 25 by Sonoma County Superior Court Judge Bradford DeMeo.

His mother, Fay Romesburg, pleaded no contest to one felony charge of pandering. She will be sentenced to one year in the county jail followed by three years on probation.

Prosecutors said the Romesburgs operated a prostitution ring in the cities of Rohnert Park and Santa Rosa for nearly 10 years, selling sex with dozens of adult women. “The mother-son duo orchestrated all aspects of the victims’ sex work in exchange for money, sex and other benefits.

Profits were then laundered through various front businesses and financial institutions,” the press release stated.

Rohnert Park public safety officers arrested the Romesburgs Jan. 26 following an undercover investigation. Internet ads for massage services placed by the Romesburgs showed photographs of women and indicated that clients could ask for “upgrades,” police said, and the listed phone number was associated with Fay Romesburg, police said.

An undercover Rohnert Park police officer who set up an appointment for a massage at an apartment rented by David Romesburg was offered a sex act in exchange for money, police said.

In a jailhouse interview the following month, Fay Romesburg denied any wrongdoing. She said she rented rooms to women who were self-employed and would have a hard time proving income to most landlords.