Prosecutors won’t be filing criminal charges against anyone after a boating accident in Wareham this July ended in the death of an 8-year-old boy from Sudbury.

Plymouth County District Attorney Timothy Cruz announced the decision on Monday. According to a press release from the District Attorney’s office, the state Office of the Chief Medical Examiner performed an autopsy on Harry O’Connor and found that “the manner of death was ruled an accident.”

O’Connor died July 29 days after the boat he and 11 others were aboard capsized in rough seas in Hog Island Channel. Nine children and three adults were on the 24-foot Four Winns Horizon powerboat when it overturned near Stony Point Dike at approximately 4:30 p.m. on July 26.

The Coast Guard, Buzzards Bay Task Force, good Samaritans, Marion Harbormaster Department the Wareham Department of Natural Resources and Onset Fire officials all participated in the rescue.

O’Connor was submerged beneath the boat after it capsized. He was pulled from the water by Mike Margulis, a commercial diver from Marion who happened to be in the area at the time. O’Connor was unresponsive when taken from the water. He was flown to Boston Children’s Hospital where he later succumbed to his injuries.

The decision to not file criminal charges follows an investigation by the Massachusetts Environmental Police, State Police, the United States Coast Guard, Wareham Police and the Wareham Department of Natural Resources and Marion Harbormaster.

District Attorney spokeswoman Beth Stone said because no criminal charges are being filed the identities of the adults on board are not being released.