Search efforts continued Tuesday for six people after a superyacht sank off the coast of Sicily during what reportedly was a celebratory cruise for British tech entrepreneur Mike Lynch after he was acquitted of fraud and conspiracy charges in the U.S.

The U.K.-flagged Bayesian was moored off the coast of Porticello with 22 people on board when its believed to have been struck by a small tornado called a waterspout around 4 a.m. Monday, Italian authorities have said.

The luxury vessel quickly capsized and sank about 164 feet into the depths (roughly the equivalent of a 15-story building). Everyone missing is believed to be dead, a spokesperson for the Italian Coast Guard told Bloomberg on Tuesday.