BANGOR, Maine — How a father-daughter duo allegedly ran a drug distribution ring in the Dexter area for more than a dozen years may become clearer during their joint trial on federal drug charges set to begin Aug. 15.

Roger Belanger, 58, of Corinna and his daughter, Kelli Mujo, 30, of Wellington and Central Falls, Rhode Island, are to be tried before a jury in U.S. District court on one count each of conspiracy to distribute and possess with the intent to distribute 5 kilograms or more of cocaine and an unspecified amount of oxycodone and using or maintaining a drug-involved place between Jan. 1, 2002, and Nov. 22, 2014.

Belanger and Mujo were indicted with eight others, who have since pleaded guilty, in April 2015 by a federal grand jury. Seven of them are listed as potential witnesses by the prosecution.

Belanger and Mujo are free on bail with restrictive conditions that include electronic monitoring and home detention.

Assistant U.S. Attorney Joel Casey declined to comment on the upcoming trial, but his brief, filed last month, provided some details about how the operation worked.

Belanger in 2002 began obtaining large quantities of cocaine in Rhode Island and arranging for couriers to bring it to Maine, the 16-page brief said. One of those couriers was Mujo.

When Belanger mover to California in 2004 or 2005, Mujo took over her father’s operation, the brief said. A few years later, Belanger returned to Maine and began selling cocaine again with his daughter. Around 2011, Mujo allegedly began obtaining oxycodone from her Rhode Island source along with cocaine.

The U.S. Drug Enforcement Administration in August 2014 obtained court orders to wiretap the cellphones of Belanger, Mujo and other members of the conspiracy, the brief said. That allowed the government to obtain search warrants for Belanger’s residence and garage in Corinna and Mujo’s residence in Harmony. What if anything was seized was not included in the brief.

Mujo’s attorney, Stephen Smith of Augusta, filed a two-page trial brief last month that said the defense planned to call no witnesses and no experts. Belanger’s attorney, Jon Haddow of Bangor, did not file a trial brief but said last week that he did not plan to call witnesses or experts, either.

Mark Tasker, 48, of Dexter; his son, Greg Tasker, 27, of Stetson; Antoinette Perreault, 47, of Harmony; and Eugene Moulton, 67, of Harmony, each pleaded guilty last month to a drug conspiracy charge. The elder Tasker also pleaded guilty to one count of using or maintaining a drug-involved place.

The Taskers are being held without bail while awaiting sentencing. Perreault and Moulton, who live together, remain free on $5,000 unsecured bail each.

In January, Whitney Chadbourne, 32, and Corey Pomerleau, 24, both of Harmony, and John Williams, 39, and his wife, Cynthia Williams, 43, both of Stetson, each pleaded guilty to a drug conspiracy charge. All are being held without bail.

All but Mark Tasker are listed as potential witnesses for the prosecution at the trial of Belanger and Mujo.

All defendants who have pleaded guilty, except Mark Tasker, face up to 20 years in federal prison and a fine of up to $1 million. Mark Tasker, along with Belanger and Mujo, faces between 10 years and life in prison on the drug conspiracy charge because of the amount of cocaine allegedly distributed and a fine of up to $10,000.

On the charge of using or maintaining a drug-involved place, all three defendants face up to 20 years in federal prison and a fine of up to $500,000.