Six other officers were missing after the Taliban attacked police checkpoints in Arghandab district, in Kandahar province, said Abdul Hakim Jan, a police officer.
The attack in the strategic area of Arghandab, 25km north of Kandahar city, came weeks after Afghan and foreign troops forced the Taliban militants to relinquish control of the town, which they had briefly captured.
During Friday's attack, the militants ambushed police checkpoints set up to keep the Taliban fighters away from the town, and beheaded seven policemen, said a purported Taliban commander in the area Mullah Mohammad Nabi.
Australian soldier killed
An Australian soldier was killed on Friday during an attack on Taliban bomb-makers in Afghanistan, the country's defence chief said. It was Australia's third combat death in the conflict, all in the past two months.
The death of Pvt Luke Worsley, 26, came on the eve of federal elections in Australia, but was unlikely to influence voters since both major parties have expressed equal support for Australia's role in the conflict.
Air Chief Marshal Angus Houston said Worsley was killed in in Uruzgan province.