Four Rockville business owners face charges that the spas they ran offering massages and acupuncture were actually brothels, county police said in a news release on Friday.

The release details a police investigation of six businesses that began in September after police noticed an uptick in the number of acupressure and massage parlor advertisements in the adult section of websites that cater to adult services.

Police have charged owners of the following businesses, according to the release:

• Executive Body Work, 966 Hungerford Drive, Suite 14A. Mauricio Alex Garcia Guardia, 31, of the 14000 block of Westbury Drive in Rockville, is charged with conducting prostitution and human trafficking. A warrant has been issued for his arrest.
• Tropical Spa, 620 Hungerford Drive, Suite 16. Howard Hao Wang, 48, of the 19100 block of Forest Brook Road in Germantown, is charged with human trafficking and conducting prostitution. Wang also operates Best Massage, at 966 Hungerford Dr, Suite 11A, according to the release.
• Pink Spa, 932 Hungerford Drive, Suite 12A. Roberto Carrasco, 47, of the 1500 block of North Pierce St. in Arlington, Va., is charged with conducting prostitution.
• Ya Ya Spa, 751 Rockville Pike, Suite 1B, Rockville. Feng Liu, 46, of the 100 block of Orchard Drive in Gaithersburg, is charged with human trafficking and conducting prostitution.

"Detectives utilized a new Maryland law that provides an exception to the Maryland Wiretap Law for investigations that involve human trafficking," the release said.

"In the past, the owners/operators of these establishments, much like 'pimps', created enough space between themselves and the business operations that allowed them to be immune from criminal accountability," the release states. "Investigators determined that illegitimate massage and acupressure businesses operating in the county had become the havens for human trafficking schemes and were exploiting the most vulnerable women as tools for profit."

Montgomery County police ask that anyone with information about the suspects or businesses involved in this investigation or information about illegal activity at other massge businesses call the Montgomery County Special Investigations Division-Vice and Intelligence Unit at 240-773-5958.