Eight people were detained Friday in connection with a brush fire which killed six Croatian firemen a day earlier, Croatian police said, DPA reported. Five firefighters died on the scene when fire encircled them on Kornat, an island off Zadar on the Adriatic coast and another man succumbed later. Doctors in Zagreb were fighting for the lives of five others with grim injuries, such as third and fourth degree burns covering up to 90 per cent of their skin. Police was investigating the cause of the fire and was interrogating the eight people detained under suspicion that may have been involved, a statement said. The suspects were construction and tourist workers, reports said. Earlier reports said that a German tourist had caught the apparent arsonists on a video, but police did not mention that detail. The fire on Kornat, the largest island in the Kornati archipelago, a national park comprising 150 islands spread over 320 kilometres square, erupted Thursday early afternoon. Experts criticized the decision to deploy the firemen to the uninhabited covered by tall, dry grass. The men were not equipped well enough to survive once the wind changed and fire encircled them. The blaze has been spreading at an amazing speed of 30 square metres per second, forcing tourists to leap into the sea, a surviving firefighter, Nikola Kurkut, said. The tourists were evacuated to the shore earlier, but some of the firemen were caught further from the water, he said. "It was horrible. When we dragged them out of the fire, they were melted like plastic," Kurkut told the Vecernji List daily. The fire was eventually extinguished Friday morning by a Canadair aircraft, the defence ministry said.