Police in Kenya say one of their officers has been beheaded by members of the illegal Mungiki sect.
Recent grisly murders have shocked Kenyans
The decapitated body was discovered by residents in the town of Gatundu, about 40km north-east of Nairobi.
The Mungiki sect - described by the authorities as a criminal gang - has been blamed for a series of gruesome killings and beheadings.
In June, some 100 people died in a major police operation against the sect in one of Nairobi's biggest slums.
The Mungiki claim to take their inspiration from Kenya's Mau Mau rebels.
Mungiki followers have been demanding protection fees from public transport operators, slum dwellers and other businessmen in and around Nairobi.
Those who refuse are often brutally murdered.
The Mungiki are made up primarily of militants from Kenya's biggest ethnic group, the Kikuyu. The sect was banned in 2002.
Some commentators have linked them to politicians wanting to cause unrest and fear ahead of December elections.