A dozen people were arrested Tuesday in Augusta on drug-related charges, the result of a months-long investigation into the sale of narcotics in Augusta and the midcoast region, said Peter Arno, a commander from the Maine Drug Enforcement Agency, in an afternoon news release.

Authorities made the arrests at five locations around the city after investigating the sale of crack cocaine and heroin by out-of-state dealers, Arno said. Those arrested came from Massachusetts and Maine, with charges that included conspiracy to traffic, aggravated trafficking and — in one case — possession of a scheduled drug.

They made the arrests after seizing about 50 grams of crack, 12 grams of heroin, five handguns — one of which was reported stolen — and about $4,000 in cash police believed resulted from drugs sales, Arno said.

Police estimated the street value of the seized drugs to be $10,000. Some of the charges were aggravated because the suspects allegedly were dealing drugs within 1,000 feet of an area designated as safe under state law, such as a school, park or playground.

Here is a list of the 12 people arrested:

• Jordan Ascencio, 20, of Roxbury, Massachusetts, on a class B charge of conspiracy to traffic in schedule W drugs (heroin/crack).

• Sergio Figueroa, 21, of Roxbury, Massachusetts, on a class B charge of conspiracy to traffic in schedule W drugs (heroin/crack).

• Jose Lewis Figueroa, 24, of Roxbury, Massachusetts, on a class B charge of conspiracy to traffic in schedule W drugs (heroin/crack).

• Kidante Roberts, 21, of Boston, on a class B charge of conspiracy to traffic in schedule W drugs (heroin/crack).

• Emanuel Rocque, 39, of Augusta, on a class A charge of aggravated trafficking in schedule W drugs (aggravated because of the alleged presence of a handgun).

• Dalene Black, 34, of Augusta, on a class A charge of aggravated trafficking in schedule W drugs (aggravated because of the alleged presence of a handgun).

• Philip Theriault, 43, of Augusta, on a class A charge of aggravated trafficking in schedule W drugs (aggravated because the alleged trafficking occurred within a designated safe zone).

• Jessie Clark, 34, of Augusta, on a class A charge of aggravated trafficking in schedule W drugs (aggravated because the alleged trafficking occurred within a designated safe zone).

• Corey Collamore, 30, of China, on a class A charge of aggravated trafficking in schedule W drugs (aggravated because the alleged trafficking occurred within a designated safe zone).

• Dixie Gauthier, 38, of Wiscasset, on a class A charge of aggravated trafficking in schedule W drugs (aggravated because the alleged trafficking occurred within a designated safe zone).

• Lisa Gosselin, 41, of Wiscasset, on a class A charge of aggravated trafficking in schedule W drugs (aggravated because the alleged trafficking occurred within a designated safe zone). Gosselin was arrested in February 2016 and charged with the Dec. 22, 2015, theft of grow lights from a store in China. At the time, police said she and two others traded the lights for heroin.

• Michael Gregg, 51, of Augusta, on a class C charge of possession of schedule W drugs. Gregg was charged but was not at the Kennebec County jail late Tuesday afternoon.

The 12 were arrested at five locations in Augusta, according to Arno: Apartment A at 42 Mount Vernon Ave., Apartment 5 at 38 Water St., Apartment 1 at 9 Bond St., and two rooms in an unidentified motel.

Police made the arrests after making an undercover purchase of heroin from the group, Arno said. Officers from the Maine Drug Enforcement Agency, state police, Augusta police and the Kennebec County Sheriff’s Office took part in the arrests.

The 12 suspects were brought to the Kennebec County jail, and the investigation probably will result in more arrests, Arno said.