Five Italian tourists died on a daring, deep-water scuba dive into an underwater cave in The Maldives — sparking a police investigation into the tragedy, authorities said Thursday.

Monica Montefalcone, a marine biology professor at the University of Genoa, and her 20-year-old daughter, Giorgia Sommacal, were 160 feet deep in the waters of Vaavu Atoll when they vanished Thursday, Italy’s foreign ministry said.

Three other adventure seekers on the trip — Muriel Oddenino of Turin, Gianluca Benedetti of Padua, and Federico Gualtieri of Borgomanero — also failed to resurface from the dive, according to the UK Sun.

Rescue crews rushed to the scuba hotspot, near the island of Alimatha, at around 1:45 p.m. and frantically searched the mouthwash-blue stretch of the Indian Ocean before discovering their bodies, officials said.

The divers had boarded the Duke of York yacht Thursday morning before taking the plunge at one of the country’s most popular diving spots, the local media outlet The Edition reported.

It wasn’t immediately known what led to their deaths.

Weather in the area was rough Thursday – with strong winds up to 30 mph — though it wasn’t clear if those conditions played a role.

Local cops have launched an investigation into the circumstances surrounding the underwater disaster, but their causes of death hadn’t been revealed.

The tragedy is the likely single worst diving accident the nation has ever seen, local officials said.