The High Court in Kerugoya has for the second time dismissed a poll petition filed by Narc-Kenya leader Martha Karua against the election of Kirinyaga Governor Anne Waiguru.
Justice Lucy Gitari also slapped Ms Karua with Sh5 million as costs.
Ms Karua will pay Ms Waiguru's lawyers Sh3 million and those of the electoral commission Sh2 million.
Following the verdict, Ms Karua said she will appeal the decision.
"It is not over. We are determined to pursue justice to the last mile," she said outside the court.
The court ordered the deputy registrar to serve her with certified copies of the case proceedings.
While delivering the judgement on Thursday, Justice Gitari said the election was free and fair.
"The results declared by Independent Electoral and Boundaries Commission (IEBC) reflect the sovereign will of Kirinyaga people," the judge said after reading the decision for four hours.
The judge said Ms Karua together with her eight witnesses failed to proof allegations that the election was marred by illegalities and irregularities.
The court said the evidence produced by Ms Karua was hearsay, contradictory and unreliable.
She cited out Ms Karua's sister Loise Wanjiku whose evidence on barring of Narc-Kenya party agents from polling stations contradicted that of Ms Karua.
The judge added that the claims by Ms Karua that the election was marred by illegalities and irregularities such as voter bribery and exclusion of her agents from polling stations are unsubstantiated.
Ms Karua had claimed the governorship election was marked by cases of voter bribery at polling stations and that her agents were barred from accessing the polling stations.
She also claimed there was forgery of the election result statutory form 37A used to transmit results from polling centers to the county tallying centre.
She added that unauthorised persons such as former Mwea MP Alfred Nderitu and businessman Juma Wambugu were illegally allowed to man the polling stations.
The former Constitutional and Justice Cabinet Minister also alleged that governor Waiguru's votes were inflated by over 48,000 votes.
However, the judge found that Ms Karua failed to proof and substantiate the claims.
"Election court is not a forum to relook afresh on the election. Courts have nothing to do with the election unless dispute arises. The evidential burden is on the petitioner who disputes.
“It should be proven to the required standard and the evidence threshold should be above balance of probabilities," said justice Gitari.
Justice Gitari also noted that on exclusion of agents from the polling stations, it is not only Ms Karua's agents were affected but also of other candidates who lacked requisite documents.
"The petitioner did not specify where her agents were barred from witnessing opening of ballot boxes. No agent allgedly bared was called as a witness in the petition. She did not produce in court list of the agents though she had submitted it to IEBC," justice Gitari added.
"Evidence is not cogent. The burden of proof remains with the petitioner. The evidence on record questions who was barred or excluded," she added.
On claims of canvassing, bribery and intimidation of voters, the judge said Ms Karua did not witness the incidents at first hand.
"The petitioner did not say who informed her. The informant is not named. The claims are hearsay," said the judge.
In the case IEBC produced nine witnesses while Ms Waiguru and her deputy Peter Ndambiri produced five witnesses.
Lawyer Kamotho Waiganjo for governor Waiguru celebrated the decision saying it was suitable as Ms Karua could not substantiate her claims.
"It is important to internalise culture of moving on after defeat. Currently in Kenya it is impossible to steal any election. The court has affirmed who voters knew they voted for," said Mr Waiganjo.