High Court Judge Lilian Mutende in her ruling said Mr Mule, who contested the Matungulu parliamentary seat on a Wiper Democratic Movement ticket, was not validly elected as MP.
Four petitioners who were losers in the polls Thomas Malinda Musau, Stephen Ndambuki Muli, John Makenzi and a former MP Moffat Maithya filed a petition against Mr Mule soon after the polls.
The case took four months.
The petitioners had complained that their agents were not allowed in the tallying centers and in some cases polling centres were opened late and closed early hence denying their supporters their constitutional right of voting.
Mr Maithya testified that he was forced out of the tallying centre despite being a candidate in the polls.
During the trial, the court ordered for a recount of votes which still placed Mr Mule in the lead with more than 2,262 votes.
But this was not enough as the judge said irregularities in the polls were enough to make her conclude that the elections were not free and fair.
She directed that only a by-election can help address the issues raised.
Mr Mule who was represented by lawyer Priscilla Kioko said he would appeal against the ruling. Source