MERRILLVILLE — An open sign remained dark and the front door was locked Friday at Seoul Spa Massage, one day after authorities raided the business and were seen escorting women out the back door.

Local, state and federal law enforcement officials executed a federal search warrant just after 9 a.m. Thursday at Seoul Spa Massage in the 2400 block of U.S. 30.

The U.S. attorney's office confirmed a warrant was executed, but a spokesman said he could not confirm or deny an investigation. Local police said the case was sealed.

A check of federal court records Friday showed no recently unsealed cases linked to the warrant.

On Friday, the business appeared closed. Fraternal Order of Police stickers covered a large portion of the locked front door.

During the raid Thursday, a woman wearing a jacket marked "victim services" was seen entering and exiting the front of the business. 

About an hour after the raid began, two women exited the back of the business and got into an unmarked pickup truck driven by an FBI agent. Agents then drove away with the women.

Ashley Nowak, a cashier at the Hookah Tobacco Plus store several doors down from the spa, said on Friday she and other employees in the strip mall had suspicions about the spa.

The spa's clientele appeared to include mostly men, many of whom avoided parking directly in front of the spa, Nowak said. 

Women from the spa came into her store to purchase cigarettes, she said.

"They were really nice," she said. "They were really quiet. They kind of kept to themselves."

Some of the younger women — who may have been in their 20s — dressed provocatively, but the older women did not, she said. 

The U.S. attorney's office confirmed a second federal warrant was executed Thursday morning at a home in the 7400 block of Taylor Street in Schererville. However, a spokesman declined to confirm or deny whether that warrant was connected to the warrant executed at Seoul Spa.