Four people were arrested on drug trafficking charges in Winthrop after an investigation by state and local law enforcement departments turned up 76 grams of heroin and about $2,400 in suspected cash proceeds, police said.

Police made the arrests Thursday and Friday after an undercover agent bought heroin and investigators found the drugs and cash at a home on Mount Pisgah Road in Winthrop, Commander Peter Arno of the Maine Drug Enforcement Agency said in a news release.

The seized heroin had a street value of around $15,500, Arno said.

Michelle St. Laurent, 28, of Winthrop, and Tyrone Lindsay, 20, of Waterbury, Connecticut, were charged with aggravating trafficking in schedule W drugs (heroin). St. Laurent also was charged with violating conditions of release.

The other two Winthrop residents who were arrested, Daniel Ackerly, 30, and Frederick Werner, 59, each were charged with trafficking in schedule W drugs.

All four were taken to the Kennebec County jail in Augusta. Authorities provided photos of all the suspects except Werner.

Agents from the Maine Drug Enforcement Agency’s task force in Augusta charged Ackerly and Werner on Thursday after an undercover agent made a heroin purchase, Arno said.

Later, investigators found the heroin and money after executing a search warrant at St. Laurent’s home on Mount Pisgah Road, Arno said. At the time, both St. Laurent and Lindsay were at the home and were arrested. Police set Lindsay’s bail at $20,000 cash, while St. Laurent was not allowed bail.

Investigators also seized other evidence of drug trafficking at the scene, and more arrests are possible, Arno said.

St. Laurent and Lindsay’s crime was classified as aggravated because of the amount of heroin seized, Arno said. As a class A charge, it’s punishable by up to 30 years of incarceration and a $50,000 fine, according to the Maine attorney general’s website.

Ackerly and Werner’s class B charge is punishable by up to 10 years in prison and a $20,000 fine. Both Werner and Ackerly’s bail was set at $2,500.

All four defendants have court dates of Sept. 22, Arno said.

Authorities with the Maine State Police, Kennebec County Sheriff’s Office and Winthrop and Monmouth police departments also contributed to the investigation.