ORO VALLEY, Ariz. (AP) -- Two women are facing prostitution charges following an investigation at a spa in southern Arizona. Oro Valley police say 44-year-old Hong Chen and 48-year-old Kongmei Wang are being held on suspicion of prostitution and practicing massage without a license. Both women have been booked in the Pima County jail. The investigation began last month when police received reports of suspicious activity at Oro Spa. Police say the investigation revealed there were multiple sex acts performed in exchange for money at the spa. It was unclear Thursday if either Chen or Wang has a lawyer yet.