Defendant found guilty in involuntary manslaughter case

Chief Judge H. Chris Ryan Jr. found Mason Shannon guilty Thursday of unintentionally killing Michael Castelli last year in rural Ottawa.

Shannon, 43, of Mason City, Iowa, is to be sentenced Friday, Nov. 16. Prosecutor Greg Sticka asked Ryan to revoke Shannon's bond and jail him. Shannon's attorney, Douglas DeBoer, said Shannon should remain free until sentencing, because Shannon has always showed for court hearings.

Ryan refused Sticka's request, saying, "I'm going to find it hard to say he's a danger to society."

Shannon's trial took place last week, with Ryan delivering his decision Thursday. Shannon opted to have Ryan decide the case, instead of a jury.

Castelli died July 20, 2017 at Bonnie Plants, a commercial tomato grower just northeast of Ottawa, where Shannon worked and temporarily lived. Shannon had invited the 32-year-old Castelli, who lived in Ottawa, to Bonnie Plants the night in question.

Castelli was hallucinating on psychedelic mushrooms and acting violently, which prompted Shannon and two other men to restrain Castelli, with Shannon putting his arm around Castelli's neck. Ryan determined Shannon maintained the hold too long, denying oxygen to Castelli's brain.

Ryan noted it doesn't take much of a hold to cut off air, which Shannon should have known. Ryan also pointed out the two other men disengaged from Castelli, after Castelli stopped struggling, but Shannon did not release his hold, even after one of the men suggested he ease up.

DeBoer contended during trial Castelli was not choked to death, but rather died from a preexisting heart condition. Ryan said he weighed the evidence, particularly the testimony of pathologists, finding Castelli died from choking.

Ryan stressed Shannon did not intentionally kill, but rather was reckless.