SAN JOSE, Costa Rica (AP) — Six people, apparently including the German businessman behind Gold’s Gym, were feared dead Saturday after a small plane crashed into the Caribbean just off the Costa Rican coast.

All five passengers were believed to be German citizens, Security Minister Jorge Torres said. The plane’s pilot was Swiss. At least one other of those aboard the plane appeared to be a relative of Schaller.

Costa Rican authorities said pieces of the twin-engine turboprop aircraft were found in the water Saturday, after the flight went missing Friday.

A flight plan filed for the small, charter plane listed Rainer Schaller as a passenger. A man by the same name runs international chains of fitness and gym outlets, including Gold’s Gym and McFit. At least one other of those aboard the plane seemed to be a relative of Schaller, but the relation was not immediately confirmed by authorities.

Martín Arias, Costa Rica’s assistant security minister, said no bodies had been found yet at the site, about 17 miles (28 kilometers) off the coast from the Limon airport.

“Pieces have been found that indicate that this is the aircraft,” Arias said. “Up to now we have not found any bodies dead or alive.”

The plane was a nine-seat Italian-made Piaggio P180 Avanti, known for its distinctive profile.

The plane disappeared from radar as it was heading to Limon, a resort town on the coast.

The security minister said the flight had set out from Mexico.

“Around six in the afternoon we received an alert about a flight coming from Mexico to the Limon airport, carrying five German passengers,” Torres said. A search started immediately but was called off temporarily due to bad weather.

Rainer Schaller is listed as “Founder, Owner and CEO of the RSG Group,” a conglomerate of 21 fitness, lifestyle and fashion brands that operates in 48 countries and has 41,000 employees, either directly or through franchises.

Schaller was in the news in 2010 for his role as organizer of the Berlin Love Parade techno festival. A crush at the event killed 21 people and injured more than 500. Authorities at the time said Schaller’s security failed to stop the flow of people into a tunnel when the situation was already tense at the entrance to the festival grounds.

Schaller fought back against the accusations of wrongdoing, noting that his security concept received official city approval.