Nan Son Yim, 71, was taken into custody on Wednesday after detectives executed a search warrant at Crystal Spa on the 1700 block of Foulk Road.
Detectives say they identified three women who worked there as victims of human trafficking.
The women were allegedly forced to work 12-hour shifts, seven days a week, without proper compensation.
Nan Son Yim has been charged with Human Trafficking, Promoting Prostitution and Conspiracy.
She was taken to Delores J. Baylor Women's Correctional Institution after failing to post $108,000 cash bail.
Investigators also arrested 78-year-old Thomas Hofer and 45-year-old Jesse Wasmer inside the spa and charged them with Attempting to Commit Patronizing a Prostitute.
Detectives say they are actively searching for the owner of Crystal Spa, identified by police as 54-year-old Meilan Quan.
They say a search warrant of Quan's home in Claymont, Delaware, provided evidence linking her to the alleged operation.
Quan is believed to have connections in both Delaware and Flushing, New York.
Anyone with any information on her whereabouts is asked to contact New Castle County police.
Tips may also be submitted to the New Castle County Division of Police 24/7 Human Trafficking Hotline at (302) 395-2727.