STROUD MP Neil Carmichael is among several sitting Tory MPs who may be investigated by the police for possible election fraud in the 2015 General Election.
The investigation centres on whether costs to transport and accommodate bus-loads of Conservative activists to marginal constituencies in Gloucestershire should have been declared by candidates.
It comes amid allegations that the Conservative Party may have breached election spending rules in the run up to polling day last year.
The party has insisted that spending on the campaign was in accordance with election laws.
Gloucestershire Police have confirmed that a probe has been set-up relating to last year’s general election but said they could not reveal any more while the case is active.
A spokesman from the force said: "We have received an allegation of electoral fraud and an investigation has been launched.
"We are considering an application for extension on time to investigate.
“This is in relation to the 2015 general election."
Gloucestershire Police did not specify which constituency or constituencies the allegation may refer to, or which party.
However, it is understood to be linked to the ongoing 'battle bus' scandal of Tory election expenses.
It is alleged that the cost of busing in supporters to help fight their campaigns should have been met by the MPs, but was instead met by the party.
If the MPs had paid for this from their own election purse it would have put them over the spending threshold allowed under election rules, it is alleged.
There are currently six Conservative MPs in Gloucestershire.
in Stroud, Mr Carmichael won a comfortable victory against his old Labour rival David Drew in May last year.
The probes are understood to be looking at election expenses of ten sitting MPs so far, including Cheltenham MP Alex Chalk.
Eight police forces have launched investigations.
The Gloucestershire police inquiry comes after the Electoral Commission met police and prosecutors last Wednesday in an attempt to ensure they do not run out of time to launch possible criminal investigations.
The commission believes its investigation into alleged breaches of reporting obligations will take at least another month, potentially taking it past the one-year time limit for launching criminal proceedings.
The claims relating to Conservative spending, covering the general election and three parliamentary byelections, were first raised by the Daily Mirror and Channel 4 News.
Paul Hodgkinson, leader of the Liber Democrats in Gloucestershire, said: “I’ve been watching the story unfold over the last couple of weeks and it’s worrying because we all have to abide by the election rules and we have to make sure we stay within them.
“If any political party has stepped over that it is concerning… we need a level playing field.
“It would effectively be buying an election. Clearly we have to wait and see what happens.”
The party has blamed an "administrative error" for failing to register some accommodation costs.
But David Cameron has insisted it was right to include such expenditure as part of the national campaign.
Meanwhile, a 38 Degrees petition calling for the MPs under investigation to be suspended from parliament until they are over has gathered nearly 12,000 signatures.
It says: “As the police have started to investigate allegations of election fraud by Conservative MPs during the 2015 General election, we the undersigned demand that those suspected MPs be suspended from parliament for the period of those investigations.
“MPs who may be guilty of fraud should be forbidden from voting on the legislation brought before parliament.
“We call upon the speaker to immediately suspend those members from the House of Commons.”