AUGUSTA — The third of a trio of defendants accused of manufacturing methamphetamine in Monmouth pleaded guilty Wednesday in Kennebec County Superior Court to unlawful trafficking in scheduled drugs.

Robert F. Dumont Jr., 28, of Monmouth, was sentenced to three years in jail with all but 15 days suspended and two years’ probation.

The other two men, Brandon A. Proctor and James W. Renaud, had pleaded guilty previously in the same court.

Proctor, 43, of Oxford, was sentenced in December to four years in jail with all but 15 days suspended and two years’ probation and fined $400.

Renaud, 34, Dumont’s brother, was sentenced in August to four years in jail with all but 41 days suspended and two years’ probation. He, too, was fined $400.

Renaud’s Monmouth home was raided last June after a Maine Drug Enforcement officer saw him purchasing pseudoephedrine — a key methamphetamine ingredient — and later “burping” or releasing pressure in a bottle in which police say methamphetamine was being made.

Several other people were sentenced Wednesday in separate hearings in Kennebec County Superior Court:

• Larry Earl Bowler, 34, of Monmouth and Winthrop, unlawful possession of scheduled drugs and violating a condition of release March 30 in Monmouth; nine-month jail sentence, $400 fine.

• Bradford Christopher, 33, of Gardiner, theft by unauthorized taking or transfer May 1-30, 2011, in Pittston; $500 fine, $6,500 restitution.

• Donald R. Reid, 50, of Augusta, cultivating marijuana Jan. 28 in Augusta; 18-month jail sentence, all but 60 days suspended, two years’ probation, $400 fine.

• Wyatt D. Wilson, 35, of Augusta, theft by unauthorized taking or transfer and criminal mischief March 18 in Augusta; two-year jail sentence, all suspended, two years’ probation consecutive to a current probation.