Joseph VanWert, left, and Randy Lambach, right, are being held on human trafficking and prostitution charges.

Two men have been accused of running a prostitution ring out of a senior living facility in Massachusetts, with one victim thought to be as young as 15.

Joseph VanWert, 65, and Randy Lambach, 45, were arrested on human trafficking and prostitution charges and are being held without bail pending a court hearing next week.

Investigators were told some of the victims used to be Lambach's foster children.

Police in Pittsfield say the arrests came after they noticed an increase in prostitution in certain parts of the city in the spring of 2017, with women involved showing a pattern of drug abuse.

An investigation eventually led to Lambach, who officers say would recruit women with "severe addiction issues".

VanWert used his residence at a Pittsfield senior living facility in North Street as a place to conduct the prostitution, police added.

"This investigation revealed that over several years, those charged have been involved in Human Trafficking," Pittsfield Police Department's Lt Michael Maddalena said in a statement on Tuesday (21 November).

"The women were recruited by Lambach, then photographed and advertised on social media sites. Lambach facilitated meeting locations with prospective 'johns' and transported these women to specified locations.

"He would often wait nearby to take a portion of the earnings. He would also compensate the women with narcotics in lieu of cash. This included heroin, cocaine and prescription medication."

One woman told police she was prostituted by Lambach for about a year and had sex with him for money or to pay off debts, the Berkshire Eagle reported.

Lambach photographed her and placed advertisements on, she added.

Men would then contact Lambach via cellphone and agree a time and location to meet. Rates were typically $80 for 30 minutes or between $160 and $200 for an hour, with the woman earning as little as 10% of the fee.

Lambach allegedly threatened to turn women over to the police if they stopped working for him, saying they wouldn't be believed and would be seen as, "drug addicts and whores."

Police were told some of the women Lambach had recruited used to be his foster children, with one possibly as young as 15 years old.

VanWert would also allegedly have sex with some of the women, and would be paid by Lambach in drugs and money for the use of his apartment.

Lt Maddalena said officers are making every effort to help to the victims in the case.

VanWert, of Becket, and Lambach, of Pittsfield, face charges of human trafficking, deriving support from a prostitute, knowingly permitting prostitution on the premises, and sexual conduct for a fee.

They face a dangerousness hearing on Wednesday (29 November) to determine if bail should be granted and at what amount.