The vessel was hit by the tornado at around 5 a.m. Monday, according to a spokesperson for Italy’s Coast Guard. The yacht was anchored about a half a mile from the port of Porticello on the Mediterranean island.

Four Britons and two Americans are among those missing, the spokesperson said.

A source told CNN that Lynch, the founder of software giant Autonomy, was a passenger on the yacht. The source spoke to CNN on the condition of anonymity, as they were not authorized to speak to the media.

Fifteen people were rescued, including Lynch’s wife Angela Bacares, and one child was airlifted to the children’s hospital in Palermo. Eight people were hospitalized in total, according to the mayor’s office. One body was found on the hull of the yacht, the Coast Guard said.