A fresh Police and Crime Commissioner election will be held after a disbarred candidate won.
Conservative candidate Jonathon Seed gained 100,003 first and second preference votes in the Swindon and Wiltshire election.
News of an historical driving offence which made him ineligible did not emerge until Sunday after polls had closed.
Wiltshire Police said it was assessing how to proceed.
'Publish full facts'
"We will now be working closely with the PARO [Police Area Returning Officer] to understand the full circumstances surrounding this situation.
"It would not be appropriate to comment further at this time," the force added.
When all the first preferences were counted, Mr Seed had 84,885 votes, nearly 50,000 more than second-placed Liberal Democrat candidate Liz Webster but not enough to avoid the vote going to second preferences.
With second preference votes counted, Mr Seed gained 100,003 and second placed Liberal Democrat candidate, Liz Webster, polled 58,074 votes.
Liberal Democrat candidate Liz Webster added that Mr Seed had treated voters with "total contempt".
She added: "He has betrayed their trust, wasted their time and a vast amount of public money.
"Re-running this election will cost tax payers £1.4m, require residents to go to vote again and deny our tired elections staff their well deserved break. All of that is an absolute disgrace.
"I am ready to fight again to be a powerful voice for the victims of crime, champion our dedicated police officers and staff, and to take the action needed to make our communities safer and bring law breakers to justice."
Labour candidate Junab Ali said: "I demand that the Conservative Party and Jonathon Seed publish full facts on the timelines of when they were first aware of this issue and apologise unreservedly to the people of Wiltshire for their failures in this case."
He also called on the party to offer to pay the full costs incurred by the "abortive process" for all parties including public bodies, candidates, their agents, parties, volunteers and the press and media.
"For the record I have never had any convictions for any offence," Mr Ali said.
Independent candidate Mike Rees said he was "disappointed" this had happened and he held Mr Seed responsible.
Prior to withdrawing, the Wiltshire councillor said he was advised by his party that a 30-year-old drink-driving offence would not affect his application, on which basis he had mistakenly believed he was eligible to stand.
However, the legislation creating Police and Crime Commissioners (PCCs) places a stricter bar on historical offences than other elected positions.
Guidance on the Electoral Commission's website states that candidates cannot stand for election if they have ever been convicted of an imprisonable offence.
This disqualification applies even if the person was not imprisoned for that offence or if the conviction has been spent.
Earlier Mr Seed, via his legal team, released the letter he sent to Terence Herbert, PARO for Swindon and Wiltshire, on Sunday.
In the letter Mr Seed states he had always been open with the Conservative party about his 1993 conviction, and that he had been reassured it did not prevent him from standing as a PCC candidate.
Mr Seed said that "at all times up until the evening of 6 May" he had been told, by party officials, that he was able to contest the election.
Local Conservative MPs Robert Buckland, James Gray and Justin Tomlinson declined to comment on Mr Seed's situation when approached by the BBC.
Other first-preference votes in the Swindon and Wiltshire PCC election were; Junab Ali (Labour) 34,147 votes, Mike Rees (independent) 31,722, Brig Oubridge (Green Party) 16,606 and Julian Malins QC (Reform UK) 4,438.