John Githongo had fled after receiving death threats
Kenya's former anti-corruption chief John Githongo has called for amnesty for those willing to admit guilt for economic crimes and corruption cases.
He said Kenya must deal with past corruption cases or they would continue to haunt the country.
Mr Githongo, who has been in self-imposed exile for three years, is on his first visit back to the country.
Prime Minister Raila Odinga welcomed Mr Githongo home, saying Kenya needed to deal with its past transparently.
Mr Githongo fled to the UK in 2005 saying he feared for his life, after accusing senior members of the government of "massive looting".
As the government's permanent secretary for ethics and governance, he exposed the notorious Anglo-Leasing scandal, which forced the resignation of several ministers.
The scam involved state contracts worth more than $1bn (Ł0.5bn) being secretly awarded to phantom firms.
Members of the new coalition government that took office this year following post-election violence invited Mr Githongo to return home.
Addressing a public forum on fighting graft in the Kenyan capital, Nairobi, Mr Githongo said economic crimes must be resolved quickly and transparently.
"The temptation to subject economic crimes to prolonged processes and the deliberation of committees not only delays justice but makes ultimate accountability less likely," he said.
Mr Githongo noted that there was a myth that corruption does not really matter as long as the economy is growing.
"If you have high economic growth [and] a high level of corruption... then corruption causes political contradictions that leads to the kind of difficulties we had in Kenya at the end of last year," he said.
He said that following the violence which rocked the country after the contested December elections, Kenya is in a fragile condition.
Earlier this year, the government and the opposition formed a grand coalition after post-election violence threatened to tear the country apart.
The coalition is a temporary instrument in the resolution of the country's problems, the former graft investigator said.
The diffusion of executive powers, he said, which led to the creation of the prime minister's office, is the first of many important steps the country needs to take.
Mr Githongo said the country had so far failed to address the causes of the post-election crisis.
"We have swept them under the carpet with committees and I know how this happens as I have served in government," Mr Githongo said.
"These issues will not be resolved over night, it will require a seismic shift."
Mr Githongo said a number of African countries were going through "a democratic recession".
Referring to recent elections in Kenya, Nigeria and Zimbabwe, and the coup in Mauritania, he said these developments were a formula for the destabilisation of entire parts of the continent.