(CBS 11 News) DALLAS A total of 27 people were either detained or arrested after law enforcement agencies across the City of Dallas joined forces Wednesday and raided eight separate businesses that they say were operating as houses of prostitution.

Four people were arrested and 23 others detained at the spas and bathhouses that allegedly operated as brothels.

Dallas Police Department Sergeant Gil Cerda says 13 more warrants have been issued.

Wednesday mornings search and arrest warrants were executed by the vice unit from the Dallas Police Department, along with agents from the Federal Bureau of Investigations, Immigration and Customs Enforcement, Internal Revenue Service and the Dallas County District Attorney's Office.

The raids, at the businesses listed below, were the culmination of an eight-month long investigation into illegal operations.

The investigation focused on the activities of the property owner's, all of which are women.

Police say operations at the bath houses went beyond serving men who just want sex. "The types of crimes that we are talking about is engaging in organized criminal enterprises, which is a prostitution enterprise," said Deputy Chief J.A. Bernal, Dallas Police Department.

• Nagoya Body Bath
  1710 W. Mockingbird, Suite A
  
• Oasis Body Bath
  1710 W. Mockingbird, Suite B
  
• Venus Body Bath
  8300 Harry Hines, Suite A
  
• Caesar’s Body Bath
  8300 Harry Hines, Suite B
  
• Asian Tan
  2001 W. Northwest Highway, #110
  
• Tokyo Sauna Spa
  11076 Harry Hines, Suite B
  
• Julia Body Bath
  11181 Denton Drive, Suite 110
  
• Royal Sauna and Bath
  2691 Freewood Drive, Suite B

Officials say illegal activity at the locations included - engaging in organized criminal activity, aggravated promotion of prostitution and money laundering.

Law enforcement officials say they are also investigating the possibility that some employees of the businesses may be victims of human trafficking.