A suspected brothel on Post Road in Warwick, which the police and immigration authorities raided earlier this month, appears to be linked to two others in Providence and Central Falls, according to a search warrant affidavit.

The police said they have evidence that the “spa” at 1550 B Post Rd., Warwick, is a front for prostitution and is connected to a Sheridan Street “spa” in Central Falls, which “appears to be supplying the female Asian employees,” and the Central Health “spa” in Providence, which is listed as the subscriber for the electric utilities, according to the affidavit.

Federal immigration authorities determined the link with Central Health after they conducted a utility check with National Grid, the affidavit said.

“We’re working with other law enforcement agencies” to investigate the relationship of the businesses, said Warwick police Detective Capt. Michael Babula. “The investigation is in progress.”

Providence Police Maj. Thomas Oates, head of the department’s investigative unit, said on Friday that he was not aware of the findings in the affidavit.

Meanwhile, the police have found no evidence that three Korean women questioned at the scene of the April 9 raid were victims of human trafficking, Babula said. Two of the women are U.S. residents. The third has an outstanding deportation order but was released along with the other two since she “is not a danger to anyone,” he said, and has attended hearings on her case with immigration authorities.

The women –– two in their early 50s and the third in her 40s — are not the target of the investigation, Babula said. Federal immigration agents are no longer involved in the investigation, he said.

The April 9 raid followed complaints from neighbors, he said, who were “concerned about the real nature of the business being conducted there.”

An undercover Warwick police detective visited the spa twice — on March 27 and 31 — and paid $60 for a massage. In both instances, the massage ended with the detective being offered sexual services for an additional $60 to $140, according to the affidavit.

During the raid, the police seized $380, receipts and other documents, two cell phones, a laptop computer, a digital video recorder, assorted DVDs, mail and assorted credit cards, according to documents filed in Kent County Superior Court.

Assistant Attorney General William Ferland said Friday that the records seized from 1550 B Post Rd. are being analyzed. Some of the records are in foreign languages, he said, and need to be translated.

Rhode Island has no law against prostitution that occurs indoors. However, Warwick police obtained the affidavit under the state law against pandering, which generally makes it illegal to operate a house of prostitution, or receive the proceeds from prostitution, both felonies.

larditi@projo.com