A monthslong investigation into the overdose deaths of women in Groton and Montville last year has led to federal heroin distribution charges against two men.

Nestor “Beans” Santana, 29, of New London and James Butler, 23, of Montville each were arrested Tuesday on federal charges of possession with the intent to distribute heroin and distribution of heroin, according to a written statement from U.S. Attorney Deirdre M. Daly.

The charges stem from an ongoing statewide initiative targeting narcotics dealers who distribute heroin, fentanyl or opioids that cause death or serious injury to users.

In this case, the arrests are linked to the overdose deaths of two women — the May 29, 2016, overdose death of 17-year-old Olivia Roark of Griswold at a Groton motel and a May 31, 2016, death of a 34-year-old whose body was discovered at a Route 32 apartment in Montville.

Santana is accused of supplying the mix of heroin and fentanyl that ultimately led to both deaths.

Investigation revealed that Ramon Gomez, who knew Roark was under the age of 18, brought her to the Flagship Inn and Suites on Gold Star Highway in Groton to engage in prostitution, authorities allege. On the morning of May 28, 2016, Gomez sold a quantity of heroin to another individual who then distributed the heroin to Roark.

In the early morning of May 29, 2016, Groton Town police and emergency medical services personnel responded to Roark's room for a suspected drug overdose. Roark was administered two doses of naloxone, which were unsuccessful in reviving her. She was transported to Lawrence + Memorial Hospital, where she was pronounced dead.

Authorities said they traced the heroin that caused Roark's death back to Santana.

In the Montville case, it is alleged that the unidentified victim was supplied with heroin and/or fentanyl by Butler, who in turn was supplied by Gomez, who in turn was supplied by Santana, officials said.

Police said Butler regularly visited with the victim to "get high," and would pool his money with her to buy heroin, according to the arrest warrant affidavit in the case. In an interview with police, Butler said he recalled the last time he got high with her she was also drinking a box of wine and alive when he left her apartment.

The state Office of the Chief Medical Examiner determined the cause of the 34-year-old female’s death to be “acute ethanol and fentanyl intoxication.”

In August and September 2016, investigators made controlled purchases of heroin from Santana. Santana was arrested on state charges on Sept. 29, 2016. A search of his residence at 82 W. Coit St., Apt. 1, in New London revealed heroin and packaging material. At the time he was charged with possession of narcotics, possession of narcotics within 1,500 feet of a school and possession of narcotics with intent to sell.

Santana and Butler appeared before U.S. Magistrate Judge Joan G. Margolis in New Haven and were ordered detained. The charge carry a maximum term of imprisonment of 20 years.

Gomez, 41, of Uncasville was arrested  by Groton Town police and since has pleaded guilty to federal sex trafficking of a minor and heroin distribution charges. He awaits sentencing.

This ongoing investigation is being conducted by the Drug Enforcement Administration, state police, the Statewide Narcotics Task Force – East, the Regional Community Enhancement Task Force and Groton Town, Montville and New London police.

Assistant U.S. Attorney Douglas P. Morabito is prosecuting the case.

Day Staff Writer Greg Smith contributed to this report.