A big crocodile knocked over a canoe in a southern Philippine lake and decapitated a 10-year-old girl, police said. The girl and a classmate were on their way to their floating school, the Mihaba Floating Literacy Center, on Mihaba Lake in Agusan del Sur province when the crocodile attacked the boat, causing it to capsize, Bunawan town police officer Melchor Danuco said Wednesday. Another report said the children were on their way home from school when the crocodile attacked the boat from behind. The attack happened on Saturday but it wasn't until Monday that rescuers found the girl's headless body floating on the lake. The classmate was rescued by a man escorting the pair in another boat, said Ruel Hipulan, head of the private group that runs the school in the remote town. “It's a monster crocodile,” Hipulan said, adding that officials were hunting the animal following the attack. Police said that, based on accounts of villagers, the crocodile might be as long as 7-9 meters (23-30 feet), which would be huge, even for the large salt water crocodiles known to inhabit the lake. Attacks are rare. But the lake's waters have been swollen for the past several months, causing fish to scatter to other parts. With little to feed on, the crocodiles have become aggressive, he said. The crocodile attack has prompted the temporary closure of the school and the evacuation of about 100 residents of houses on stilts on the lake, Hipulan added. The girl, a member of the ethnic Manobo tribe who live in floating homes in the Agusan Marsh, was heading home when the crocodile attacked the boat from behind, the provincial government said in a statement. A search is on for the crocodile and 18 Manobo families have been evacuated from their homes in fear of another attack, officials said. The Agusan Marsh in southern Mindanao island is one of the country's largest, covering 113,000 hectares. It is a sanctuary for protected species, including soft-shell turtles and freshwater crocodiles.