(CNN) -- Four scuba divers drowned after a routine trip to a popular underwater cave system in southern Italy went horribly wrong over the weekend, according to the coast guard.
The party of divers lost their way while trying to find the exit from the "Blood Grotto," a red-walled cave near the tourist port of Palinuro on Italy's southwest coast on Saturday.
The divers became disoriented after kicking up mud and sand from the floor while trying to find a way out -- and instead entered a nearby tunnel which led four of the divers to a dead end, where the coast guard says their bodies were found.
Massimo Ruggiero, the coast guard commander, confirmed to CNN that the victims were Greek-born Panaiotis Telios, British-born Douglas Rizzo, and Susy Covaccini and Andrea Pedroni, both from Rome.
An Italian public prosecutor has ordered an investigation into the accident, and the equipment used by the divers was checked for faults.
Marco Sebastiani, one of the dive's five survivors, said by the time he realized the party was heading the wrong way, it was too late.
"All of a sudden the guide started to panic ... I knew something was wrong but at that point we had already entered the cave and we were going in even further. I tried to take control but it was too late," Sebastiani told Italy's Il Messaggero newspaper.
Sebastiani, who owns a diving school in Rome, said: "We suddenly found ourselves in a blind tunnel. We couldn't see anything. At that point it was panic. The agitation of the least experienced took hold. Mud and sand came up from the bottom of the cave and visibility was gone."
"We couldn't find the exit. At a certain point I managed to find my way. I took as many people as I could with me and we swam towards the light, which grew bigger all the time. When I came up, I looked around to count us and I realised that Susy, Andrea, Douglas and Panos weren't there. I dove back in and went looking for them but I couldn't see them. Then my tank ran out of oxygen."
The Blood Grotto and other submerged caves on Palinuro's coast are popular destinations for amateur divers -- and the Cilento and Vallo di Diano National Park the caves belong to is a UNESCO World Heritage site.