Fire brigade and scuba divers recovered the boat on Monday.
CNN  — 

Two Italian secret service agents and a retired member of Israel’s security forces were among the four victims from Sunday’s fatal boat accident on Lake Maggiore, northern Italy.

The Italian victims were named as Tiziana Barnobi, 53, and Claudio Alonzi, 62, a delegate of Italy’s secret service confirmed, while a spokesperson for Israel’s foreign ministry identified the Israeli victim as Shimoni Erez, 60.

The boat captain, whose Russian partner Anna Bozhkova, 50, also died in the incident, is under investigation for culpable manslaughter, according to the Italian prosecutor.

The 16-meter (52-foot) houseboat was carrying 24 people at over capacity when an apparent waterspout struck it, causing it to capsize on Sunday evening, CNN affiliate Sky Tg24 reported.

A helicopter searched for missing passengers after the boat capsized.

Some of the party managed to swim to the shore, according Sky Tg24, adding that, although five were taken to the hospital, none of the survivors sustained any serious injuries.

Divers and a helicopter were also used as part of the search and rescue operation, according to the local fire service.

The Israeli victim and another Israeli national were not expected to be on the boat, the local prosecutor said, after the two had missed a flight on Sunday, Israeli media reported.

A delegate of the Italian secret service issued a public condolence “sharing closeness and pain for the tragic event to the families of the victims.”

Italy’s military police, the Carabinieri, are assisting with the investigation, the prosecutor’s office told CNN.

Lake Maggiore is a popular destination for tourists and is shared by Italy and Switzerland.

Passengers had been reportedly celebrating a birthday party when the boat, traveling between the Italian towns of Lisanza and Dormelletto, capsized, according to Sky Tg24.