Nairobi — One Saturday 40 years ago, Kenya's most promising leader, Tom Mboya, was gunned down in a busy Nairobi street.

Although a suspect was subsequently convicted and reportedly hanged -- but this is disputed -- the book has not closed on the Mboya assassination mystery. Neither has it closed on the killings of other outstanding leaders whose lives and careers were cut short at the behest of those in power.

Despite the ritual promises to "leave no stone unturned" and vows that the truth will be revealed, "even if it takes a hundred years", the reality is that as a nation we prefer collective amnesia as a way of burying the crimes that litter the landscape.People in positions of leadership that plot such excesses do so secure in the knowledge that they will never be called to account.

After the unprecedented violence in the wake of the disputed presidential elections of 2007, it was expected that we would move fast and decisively to punish the perpetrators, both as a way of ensuring justice and to end the culture of impunity.

The government adopted the Wako commission recommendations, but when it came to the implementation, people who had something to fear placed roadblocks across the way of a special tribunal to try the ringleaders of the post-election carnage.

The Justice Waki team had however given the option of a trial by the International Criminal Court if a local tribunal would not be established. Now we are witnessing efforts to delay recourse to The Hague, yet offering very little concrete indication that a local tribunal will be established.

The lesson here is that impunity still rules, and that is the culture that must be confronted without fear.