Jersey authorities say they are "increasingly confident" they can convict former Kenya Power boss Samuel Gichuru of money laundering.
In a letter to Attorney General Githu Muigai, Jersey AG Robert MacRae said Kenya should expedite the extradition of Gichuru and former Energy Minister Chris Okemo.
MacRae was informing Githu of the decision that found a company associated with Gichuru guilty of laundering proceeds of corruption between 1999 and 2001.
"This is obviously a very significant development, as we have now proved Mr Gichuru was guilty of money laundering and guilty of criminal conduct — namely misconduct in public office, fraud, fraudulent conversion and receiving," MacRae said in his letter.
He added: "The outcome of the prosecution of Windward Trading Limited should be drawn to the attention of the Court dealing with the extradition proceeding."
On Wednesday, Windward Trading Limited, a Jersey registered company, pleaded guilty to four counts of money laundering before the Royal Court of Jersey.
The Royal Court imposed a confiscation order of £3,281,897.40 (Sh467.3 million) and $540,330 (Sh54.9 million), thereby stripping the company of all assets.
Windward admitted to laundering the "proceeds of corruption" paid out to Gichuru by 11 contracting firms between July 1999 and October 2001.
MacRae told Githu it was not appropriate for the two to begin discussions in relation to an Asset Sharing Agreement between Jersey and Kenya.
"There have been substantial prosecution costs which have been incurred over the last decade in bringing this case to court and (subject to the extradition proceedings) a successful conclusion. Nonetheless, it is important that the majority of funds confiscated are returned so that they can benefit the people of Kenya," MacRae said.
According to court documents that MacRae shared with Githu, Windward admitted to four separate instances in which it laundered money.
Windward Trading Limited pleaded guilty to on July 29, 1999, crediting £1 million (Sh142 million) and $2.9 million (Sh249 million) to its bank accounts, knowing the money was from Gichuru's corrupt dealings.
The company also pleaded guilty to transferring £449,988 (Sh63.8 million) to its bank account on May 12, 2000, knowing that it was from Gichuru's alleged criminal conduct.
Windward Trading also pleaded guilty to transferring £450,000 (Sh64 million) to its bank account on August 15, 2000, knowing that it was from Gichuru's alleged fraud.
The company also pleaded guilty to transferring £599,994 (Sh85.1 million) to its bank account on October 19, 2000, knowing that it was from Gichuru's alleged fraud.
The court documents show that Gichuru "had total control" of Windward Trading Limited between July 29, 1999, and October 19, 2001.