A two-year drug investigation has led to the arrests of 15 people in Maine, Massachusetts and Tennessee.

Maine Drug Enforcement Agency Director Roy McKinney says the suspects were arrested in what's "likely the largest drug investigation in Oxford County history."

Department of Public Safety spokesman Steve McCausland said Tuesday that the suspects distributed 7.8 pounds of heroin throughout Oxford County between January 2013 and April 2015.

We're told the drugs had an estimated street value of $3.2 million.

McCausland said 26-year-old Del Hathaway of Saco and 26-year-old Brianna Thayer of Bean Station, Tennessee were the group's main suppliers of heroin.

McCausland said Hathaway and Thayer bought large amounts of heroin from 34-year-old Brian Aquino of Lynn, Massachusetts and distributed the drug in Maine.

The investigation was led by the Maine Drug Enforcement Agency. The MDEA was assisted by law enforcement officials in Oxford County, Maine State Police and police in Massachusetts and Tennessee.

The following suspects were arrested on heroin charges as a result of the investigation...

1) Brian Aquino , 34, of Lynn, MA

2) Del Hathaway, 26, of Saco, ME

3) Brianna Thayer, 26, of Bean Station, TN

4) Brandon Blood, 23, of Bethel, ME

5) Morgan McKinney, 20, of Bethel, ME

6) Dana Ingerson, 29, of Buckfield, ME

7) Courtney Moulton, 23, of Bean Station, TN

8) Scott Billings, 24, of Milton Plantation, ME

9) Kevin Litchfield, 28, of Oxford, ME

10) Richard Labay, 38, of West Paris, ME

11) Michael Farnum, 24, of Bethel, ME

12) Jacob Santillo, 25, of Rumford, ME

13) Cameron Gervais, 26, of South Portland, ME

14) Gregory Ford, 54, of Scarborough, ME

15) Matthew Ross, 23, formerly from Westbrook, ME

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