A returning officer was on Monday grilled by officers over rigging claims in Mwea, Kirinyaga county.
According to residents, the officer was apprehended and handed to the police after he was allegedly found with extra ballot papers.
The area was tense after voting failed to kick off in some polling stations due to a shortage of ballot papers.
Voters in Kirinyaga also demanded that primaries be halted as many aspirants' names are missing.
Former Devolution CS Anne Waiguru asked the Jubilee Party to fly more ballot papers to the county before it was too late.
"They need to come quickly. We don't care whether ballot papers are black and white or coloured," Waiguru said.
Waiguru is facing it off with incumbent Governor Joseph Ndathi for the Jubilee ticket ahead of the August 8 polls.
"Jubilee Party should take the nominations seriously as we have told them following the hitches."
"People need to vote. They are losing patience and have become agitated," she told journalists on Monday.
Waiguru urged her supporters to remain calm as they wait for the papers to arrive.
"We need to vote early so that the winners are announced at daylight."
Chaos erupted after some aspirants stormed a polling station in Mwea complaining about rigging.
There were also reports of the polls delaying despite voters turning out to cast their ballot from as early as 6am.
On Friday, primaries in the county delayed significantly following a shortage of ballot papers and boxes.
Presiding officers said the party organised for transport too late and drivers were charging more than was allocated.
Jubilee's county coordinator Martin Mwangi at that time cited "a few problems".
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Jubilee cancelled all primaries after its leader President Uhuru Kenyatta accepted that they were under-prepared.
"While the party was prepared for a normal party primary, we were confronted by a full-scale general election in terms of the massive turnout," Uhuru said.