Merrimac Police have arrested a couple for allegedly running a prostitution ring out of their home.

Robert D. Jones, 32, and Marie Sue Shelley, 28, were arrested following a three month investigation into “quality of life concerns in their neighborhood.”

Police noticed increased traffic to and from the couple’s home and received several tips about suspicious activity. Police set up an undercover sting, wherein an officer replied to an ad posted by Shelley on Craigslist. The two met, according to authorities, and Shelley offered to perform a sexual act on an undercover State Trooper for $100.

Shelley and Jones were then arrested.

Shelley was charged with sexual conduct for a fee and keeping a noisy and disorderly house. Jones already had an outstanding warrant from New Hampshire for possession of heroin, Clonazepam, an anti-seizure medicine and controlled substance, and making false statements to police and violation of probation.

He is also charged with deriving support from prostitution, keeping a noisy and disorderly house, carrying a dangerous weapon and being a fugitive from justice. They were arrested on Friday and are expected to be arraigned in Newburyport District Court on Monday.