SOUTH PARIS — Law enforcement officials on Tuesday announced the arrests of 15 people indicted in what they called the largest drug investigation in Oxford County history.

Those arrested were part of a ring that smuggled Mexican heroin through a supplier in Lowell, Massachusetts, to dealers in Maine, who had imported and distributed nearly 18 pounds of heroin since 2013 in various locations throughout Oxford County, the officials said. That much heroin represents about 80,000 doses with an estimated street value of $3.2 million, they said.

Maine Public Safety Commissioner John Morris, Maine Drug Enforcement Agency Director Roy McKinney and Oxford County Sheriff Wayne Gallant announced the culmination of the two-year investigation at a joint news conference held at the Oxford County Jail in South Paris.

They made the announcement after authorities in Massachusetts on Tuesday morning arrested the man they identified as the key supplier for the ring – Brian Aquino, 34, of Lynn, on felony charges of aggravated trafficking of heroin and drug conspiracy.

McKinney said Aquino would supply two other key members of the ring – Del Hathaway, 26, of Saco, and Brianna Thayer, 26, of Tennessee – with heroin they bought at $500 a “finger” and resold for double that amount in Maine. Hathaway had moved from Lowell, Massachusetts, to Maine to oversee the distribution ring, officials said.

Although investigators believe the ring moved 17.8 pounds of heroin, officers who made the arrests seized only an ounce of heroin in Maine and 10 ounces of heroin – or nearly 2,800 doses – in Lowell.

MDEA FOCUSES ON OUT-OF-STATE DEALERS

Heroin has become an increasingly bigger problem in rural states such as Maine, where the drug is cheaper to obtain than prescription opiates. A Maine Sunday Telegram investigation this month found that drug cartels in South and Central America are funneling thousands of dollars worth of heroin to the Northeast, which they view as an emerging and lucrative market.

The result is more addicts and an increased effort on the part of political leaders, medical officials and law enforcement to combat the epidemic. In Maine, the number of people seeking treatment more than tripled from 1,115 in 2010 to 3,463 in 2014. Overdose deaths in that same period spiked from 16 to 100.

Gov. Paul LePage has called for more drug enforcement agents to deal with the illegal trafficking of drugs, especially heroin, into Maine. The state Legislature last week came up with a plan to increase funding for drug treatment and hire more law enforcement agents, although the governor has criticized the comprehensiveness, detail and timing of the plan.

“This is the path the MDEA will continue on, and that is going after the organized, out-of-state dealers and not concentrate on the individual users. There are better ways to help those who are sick with addiction. We must disrupt the out-of-state gangs and organizations,” said Morris, the public safety commissioner.

Although state and federal authorities in Maine have conducted large-scale drug investigations elsewhere in the state, particularly in urban areas like Portland and Lewiston, Morris said the Oxford County investigation shows how deeply out-of-state drug dealers have penetrated even the most rural parts of the state.

ADDITIONAL HEROIN TRAFFICKING CASES

Tuesday’s arrests come just one day after drug agents and police cracked down on what authorities are describing as a significant heroin trafficking operation based in Orland, a small, rural community in Hancock County.

In that operation Monday, police arrested three people on charges of aggravated trafficking in heroin and conspiracy to traffic in heroin. Drug agents seized 400 grams of heroin and 22 pounds of marijuana along with 750 oxycodone pills, more than a dozen firearms and $40,000 in cash from a home in Orland. That investigation took one year to complete.

“The arrests disturb a significant source of the heroin being distributed within western Hancock County,” drug agents and police said in a joint statement.

Also Monday, Maine State Police arrested two men on heroin and cocaine charges after they tried to elude police during a traffic stop along Route 202 in Alfred.

In the Oxford County drug investigation, the three officials said their agencies worked together after a state trooper made a traffic stop in 2013 that served as the launching point for the investigation, which lasted from January 2013 to April 2015.

An Oxford County grand jury indicted 15 people as a result of that investigation – all on felony drug-conspiracy charges and some on Class A felony trafficking charges, punishable by up to 30 years in prison.

“This is the poison killing our people,” Gallant said.

Morris said that in addition to charges in Maine, Aquino likely will face charges in Massachusetts for his role in the ring there.

“This investigation reveals just the staggering amount that just one group brings in to Maine,” McKinney said.

He said the MDEA has launched more drug investigations this year than in years past and plans to release some of that data later this week.

SUSPECT IDENTIFIED AT STORE, SURRENDERS

In addition to Aquino, Hathaway and Thayer, the others arrested are: Brandon Blood, 23, of Bethel; Morgan McKinney, 20, of Bethel; Dana Ingerson, 29, of Buckfield; Courtney Moulton, 23, of Tennessee; Scott Billings, 24, of Milton Plantation; Kevin Litchfield, 28, of Oxford; Richard Labay, 38, of West Paris; Michael Farnum, 24, of Bethel; Cameron Gervais, 26, of South Portland; Gregory Ford, 54, of Scarborough; and Matthew Ross, 23, formerly of Westbrook and now homeless. All those arrested had bail amounts set at between $10,000 cash and $100,000 cash.

At the time of Tuesday’s news conference, Jacob Santillo, 25, of Rumford, was still being sought for arrest on heroin trafficking and conspiracy charges.

Santillo turned himself into a state trooper Tuesday night at the Wal-Mart in Oxford after someone in the store noticed his mugshot on a big-screen television.

“Someone else recognized him,” said MDEA spokesman Scott Pelletier.

He said that after being recognized, Santillo mulled his options and decided to call 911 instead of fleeing.

“He could have fled, but he really doesn’t have the means to go anywhere,” Pelletier said.

A state trooper drove to the store and took him into custody. He was being held Tuesday night in the Oxford County Jail.

Staff Writer Dennis Hoey contributed to this report.