Jubilee Party's Erastus Karanja Muriuki on Wednesday clinched the Ruguru Ward seat after edging out Maendeleo Chap Chap candidate James Simpson Ndegwa in the by-election.
Mr Muriuki garnered 4,270 votes (51.97pc) against Ndegwa who got 3,946 (48pc) in a tight race marred by violence and low voter turnout.
At the close of voting at 5pm, only 8,248 voters (58.63pc of turnout) had cast their ballot in a ward with 14,014 registered voters.
The by-election kicked off in most stations past 7am with voters streaming in slowly as many residents opted to do daily chores first.
In his acceptance speech, Mr Muriuki extended an olive branch to his rival to work together in developing the ward.
"I am grateful to voters of Ruguru for electing me. I will serve them diligently and also welcome my competitor to join me in pushing the agenda of our people. We have been without an MCA for five months and a lot needs to be done," Mr Muriuki said after receiving his certificate.
MCC's candidate James Ndegwa was not present at the tallying centre when the winner was announced.
Earlier in the day chaos broke out at Kiamariga Police Station where an election observer Ms Martha Miano was attacked following a tussle over alleged voter bribery.
The woman who had been accused of bribery was arrested at Ndunduini polling centre and taken to a police station.
Mathira West OCPD Kiptoo Birgen said the woman arrested in the electoral malpractice was released on a Sh20, 000 cash bail pending arraignment on Thursday.
Police said they have started collecting statements and investigations were underway.