Followers of Kenya's outlawed Mungiki sect were once known for tobacco sniffing, trademark dreadlocks and praying while facing Mount Kenya.
The Mungiki sect has a violent reputation
But the sect, which was banned in 2002, has undergone a metamorphosis since it first emerged in the 1980s.
It was inspired by the bloody Mau Mau rebellion of the 1950s against British colonial rule.
Thousands of young Kenyans - mostly drawn from Kenya's largest ethnic group, the Kikuyu - flocked to the sect whose doctrines are based on traditional practices.
One theory has it that Mungiki was formed in 1988 with the aim of toppling the government of former President Daniel arap Moi. The sect was, at one time, associated with Mwakenya, an underground movement formed in 1979 to challenge the former Kanu regime.
However, the sect members has in recent years turned to horrific crimes leaving behind mutilated corpses and a trail of blood and trauma.
In 2007, Mungiki followers were accused of a series of grisly murders in Central Province, in what was said to be a revenge attack on people who had leaked information about their activities to the police.
Banned in 2002
Thought to be ethnic Kikuyu militants
Mungiki means multitude in Kikuyu
Inspired by the Mau Mau rebellion of the 1950s
Claim to have more than 1m followers
Promote female circumcision and oath-taking
Believed to be linked to high-profile politicians
Control public transport routes, extorting money
Accused of beheading police informers
For weeks, the outlawed sect members battled with public transport operators who refuse to pay protection fees to them.
Following the crisis, a crackdown on them was ordered by Security Minister John Michuki.
Police say the victims of the sect members were abducted and tortured before being hacked to death and their bodies dismembered.
But several human rights reports have in turn accused the police of killing several hundred suspected Mungiki members in cold blood.
In April 2008, the leader of the Mungiki's political wing was shot dead, sparking riots in the capital Nairobi and elsewhere.
This came two weeks after the headless body of the wife of the sect's jailed leader was found.
Mungiki followers no longer sniff tobacco in public and have traded in the dreadlocks and unkempt appearance for neat haircuts and business suits.
They extort, engage in fraud, robbery, murder and even kidnap their victims.
Media reports say the sect has evolved over the years into an organised and intimidating underworld gang with bases in Nairobi, and parts of Central and Rift Valley Provinces.
They control public transport routes and demand illegal levies from operators.
Mungiki followers reign supreme within city slums, notably Mathare in the east of the capital. Here they provide illegal water and electricity connections to hundreds of makeshift shacks.
Residents of the slums also have to pay a levy to the sect to be able to access communal toilets and for security during the night in the crime infested slums.
Despite the allegations of police brutality against the Mungiki, many Kenyans feel there is a lukewarm approach in some quarters to counter activities of the sect.
During the 2008 post-election violence, the Mungiki were accused of carrying out revenge attacks after ethnic Kikuyus were killed by rival gangs.
Kenyans were shocked by the grisly murders
President Mwai Kibaki is a Kikuyu and members of his community were often targeted by opposition supporters who said the election had been rigged.
There were some reports of police turning a blind eye to the activities of the Mungiki.
Its leadership has openly claimed to have two million members around the country and to have infiltrated government offices, factories, schools and the armed forces.
"Mungiki is a politically motivated gang of youths," says Ken Ouko, a sociology lecturer at the University of Nairobi.
"The religious bit is just a camouflage. It's more like an army unit. During the previous regime, they seemed to be complementary to the government. But now they seem to be antagonistic."
Mr Ouko suggests that security forces should infiltrate Mungiki to be able to counter its growing influence in Kenya.
But the sect operates in secrecy, a fact that is complicating efforts by the police to identify its members.