By Gitau Warigi
BBC Focus On Africa magazine
Vigilante groups are on the rise in Kenya.
The police have had some success in tackling the Mungiki group
Armed and with overt political agendas, they have a habit of surfacing when general elections are around the corner. And two such groups have been a particular security headache of late.
One is a somewhat mysterious group from around Mount Elgon in western Kenya calling itself the Sabaot Land Defence Force (SLDF).
The other, called Mungiki, is considered more ominous because it has been drawing disaffected and poor youth from the dominant Kikuyu ethnic group.
Paramilitaries they are not, but they have been a security nightmare nonetheless. The two gangs are quite different, but each has been targeting to kill government agents in their areas of operation.
The SLDF operates as a conventional militia, with an estimated strength of several hundred fighters. Its leaders are unknown, though there have been strong indicators that local politicians in the opposition-dominated area have been giving support to the militia.
Emerged in the 1980s
Outlawed in 2002
Recruits mainly from Kikuyu tribe
Strongest in Nairobi's slums where it runs extortion rackets
Poses as a traditional religious sect
Accused of trying to destabilise government
Its style is quick-strike attacks at police patrols or government outposts.
Meanwhile Mungiki's mission of destabilisation of what is essentially a Kikuyu-led government is more perplexing, as it is itself exclusively Kikuyu outfit.
Mungiki likes to pose as a traditionalist religious sect, but at other times it comes across as a pure political gang for hire - until its descended into outright criminality through an orgy of seemingly senseless killings that drew the full wrath of the state.
Mungiki is especially feared because of the macabre and secret oaths to which it subjects its initiates Yet its quasi-religious posturing has since been exposed as a false cover for its true agenda: extortion.
The gang's main target is the matatu minibuses which dominate public transport in the capital Nairobi. It has extended its extortion and protection rackets into the slum areas, where police and other law enforcers stayed away.
Small shopkeepers and especially brewers of illicit slum liquor had to make daily protection pay-offs to Mungiki to remain in business.
Like so much else in Kenya, the SLDF's grievances revolve around land. They say their ancestral land has been dispossessed as other groups have settled into the fertile Mount Elgon region.
To some extent, the government's war on the SLDF has been less effective than it has been with Mungiki because of political factors.
What sparked the Mungiki-government war was when, earlier this year, some brave matatu operators grouped together to oppose a sudden hike in the daily levies Mungiki members were demanding.
The reaction of the gang struck terror everywhere. Scores of matatu operators who had stood their ground were murdered in especially gruesome circumstances.
SABAOT LAND DEFENCE FORCE
Emerged this year as a conventional militia
Based in western Kenya
Recruits from the Sabaot, part of the Kalenjin tribe
Demanding return of ancestral land
Attacks police patrols
This forced the police to intervene with full force, but it only widened the war as Mungiki turned its attention to the government's own agents.
A full-scale crackdown in the slums and other Mungiki hideouts left the police with a clear victory, though sporadic killings by the gang are still intermittently being reported.
Yet more perceptive observers, noting the rapid success in recruitment Mungiki had been making among poor Kikuyu youths, have sounded a warning that the real time bomb is the runaway unemployment, economic despair and social alienation the government has left to fester in the urban slums and the over-crowded villages of Central Province.
Over time, Mungiki's top honchos have gone through the motions of embracing born-again Christianity, hence ostensibly eschewing their questionable past.
A man who was described as the sect's "spiritual leader" announced his transformation from Nairobi's Kamiti Prison, where he is serving time. And another who used to be the public face of the gang, Ndura Waruinge, is now a Nairobi-based Christian preacher.
But what is causing much more interest is the fact that he has declared that he will run for the Langata parliamentary seat of Raila Odinga, the current government's chief nemesis.
After his announcement he swung through the Nairobi constituency and violent clashes broke out between the supporters of the two candidates.
For security personnel, the prospects are ominous. A face-off of Mungiki and Odinga's die-hard supporters who populate the huge Kibera slum in Langata is a recipe for real trouble.
Gitau Warigi is a columnist for the Sunday Nation newspaper in Nairobi.