BELCHERTOWN — Two residents were arrested Tuesday night in connection with a suspected drug trafficking operation run out of their home.

Scott Berry, 44, and Jennifer Pierson, 31, both of 60 Perry Road, pleaded not guilty to drug-related charges in Belchertown District Court on Wednesday. Bail was set at $2,500 for Berry and $1,000 for Pierson, and their cases were continued until Jan. 31.

The arrest followed a months-long investigation by police with the Northwestern District Attorney’s Drug Task Force, according to the DA’s Office.

Berry and Pierson — who had been under surveillance for several months after authorities received numerous complaints about suspected drug sales at the residence — were pulled over on Route 202 in Belchertown at around 8:15 p.m. on Tuesday after officers observed them making brief stops in driveways and parking lots in Athol, Orange, Chicopee and Springfield, “where they engaged in interactions that were brief and consistent with drug sales,” according to a statement from the DA’s office.

Drug task force officers approached the vehicle and investigators seized approximately 1,150 bags of suspected fentanyl, 9 grams of suspected crack cocaine and a single oxycodone pill, according to the DA’s office.

Berry faces charges of trafficking in fentanyl more than 10 grams, distribution of cocaine (subsequent offense), and conspiracy to violate drug law. Pierson faces charges of trafficking in fentanyl more than 10 grams, distribution of cocaine, conspiracy to violate drug law and possession of oxycodone.

The investigation into the case remains ongoing.

Tuesday’s arrest followed the arrest of dozens of people from Greenfield, Deerfield, Montague, Ludlow, Charlemont and West Springfield earlier this month in connection with an alleged cocaine trafficking operation that investigators believe distributed between 100 and 200 grams of cocaine a day throughout Franklin and Hampshire counties and the North Quabbin.

According to the DA’s office, the investigation culminated Dec. 14, when members of the Northwestern District Anti-Crime Task Force coordinated the simultaneous execution of several search warrants, seizing the alleged criminal organization’s cocaine and other evidence.

Among the arrests were Brandon Rice of Hatfield, and West Springfield resident Daniel Rice, who owns Dapper Dan’s Barbershop on Chapman Street in Greenfield, a location that was believed to be part of the alleged criminal operation, the DA’s office said.