County returning officer Kenneth Kamenchu has been admitted to hospital after he was attacked by rowdy youths.
Kamenchu had serious head injuries and fractures on his right hand. His attackers accused him of planning to rig the Jubilee nominations in the region.
Supporters of aspirants from Runyenjes constituency accosted the official on Wednesday evening at the tallying centre.
They arrived in two lorries and demanded that the official hand them nomination certificates. They beat him after he turned down their demands.
Police officers who came to his rescue had to fire in the air to disperse the mob.
Kamenchu, who was taken to the Embu Teaching and Referral Hospital, said he lost laptops with crucial data during the attack.
Jubilee county elections coordinator Abraham Limo took over the role of returning officer and announced the gubernatorial and senatorial results.
The Mbeere South returning officer, only identified as Rose, was also attacked by a mob of youths.
They claimed that the official had hidden election materials in her handbag.
They beat her up and damaged her spectacles. They also snatched her mobile phone and other valuables.
Runyenjes MP Cecily Mbarire, who lost her governorship bid to the incumbent, Martin Wambora, said her bodyguard saved Rose from the lynch mob.
Rose said she was going to the hospital where Kamenchu has been admitted after he send for her when the youths attacked her.