SOUTH KINGSTOWN — A former EMT who the General Assembly once honored as a volunteer of the year was sentenced yesterday to serve eight years in prison after admitting he molested a coworker’s son during a 1998 camping trip.

Domenic Marchetti, 30, pleaded guilty in Washington County Superior Court last Friday to two counts of first-degree child molestation.

He was sentenced yesterday to 25 years, with 8 to serve and 17 suspended with probation. He was ordered not to have contact with the victim until November 2032.

Six other child-molestation charges were dismissed in the plea agreement.

Marchetti, then 21, molested the boy between the ages of 11 and 12 after plying him with marijuana while on a camping trip in the vicinity of Alton, according to Michael Healey, spokesman for the attorney general. The exact date and location of the incidents that lead to the charges were not known, but they were estimated to have occurred between May 31, 1998, and Aug. 31, 1998, at a site reached by boat, court records show.

The boy’s mother placed her son in Marchetti’s care while the two worked together as paramedics, Healey said.

The police said the assaults occurred once a week, on average, from the spring of 1997 through 1999 and then resumed during the summer of 1999.

The victim, who remained involved with Marchetti, reported the incidents to police last year, when he felt betrayed upon discovering him engaged with another young man, Healey said.

“He was marketing himself as a big brother-type of person when in fact he was a predator,” Healey said.

The six dismissed child-molestation charges stem from incidents that allegedly occurred between May 31, 1999, and Aug. 31, 1999, near Skunk Hill Road in Hopkinton, court records show.

The victim, who was in the courtroom when the plea deal was reached, agreed to the terms, Healey said. He has suffered significant memory loss because of the trauma of the abuse, he said.

“No question, the victim ended up living a hard and troubled life,” Healey said.

Marchetti, who had no previous convictions, served as an emergency medical technician with Hope Valley Ambulance from 1999 through 2004, according to a bio posted on the Web. Formerly of West Warwick, he worked for Universal Ambulance in Providence from February 2005 through April 2006.

The General Assembly honored Marchetti in March 2000 as the Hope Valley Ambulance Squad’s volunteer of the year.

The state Department of Health suspended his EMT license in June 2006 after learning of the charges.

Before being taken into custody, Marchetti thanked Washington County Superior Court Judge Stephen Nugent for delaying the start of his sentence until yesterday. He was given credit for time he served following his arrest in April 2006.

Marchetti, of 704 Main St., was represented by William J. Murphy, speaker of the house. Special Assistant Attorney General Erik B. Wallin prosecuted the case.

kmulvane@projo.com