Hong Chen, left, and Kongmei Wang are facing prostitution charges after an investigation at an Oro Valley spa.

Two women are facing prostitution charges following an investigation at an Oro Valley spa where police said there were sex acts being performed for money.

Hong Chen, 44, and Kongmei Wang, 48, are each facing one count of prostitution and one count each of  practicing massage without a license. Both are misdemeanors. They were booked in the Pima County jail.

The investigation began in March when Oro Valley police received reports of suspicious activity at Oro Spa, located at 10110 N Oracle Road, according to a news release for Oro Valley Police. The investigation involved Oro Valley Police, Homeland Security Investigations and the Tucson Police Department.

Over the past several weeks, the investigation revealed that there were multiple sex acts performed in exchange for money, the news release said.