The boy was swimming with friends at the Mudginberri Billabong when he disappeared, the Australian Broadcasting Corp. reported.
"It is believed the 12-year-old boy was taken by a crocodile as he and a number of other young boys were swimming in the billabong," Acting Police Cmdr. Michael White told the ABC. "One other boy, also aged 12, was bitten on the arm by the crocodile and has received medical treatment from attending St. John Ambulance members."
Police said they were searching the same area where a teenager managed to escape from a 16-foot crocodile last year.