A former MP has called for police to launch a new investigation into whether the Conservative Party breached electoral law with a leaflet drop last year.
Liberal Democrat candidate Adrian Sanders has accused the Tories of breaking the rules by delivering letters urging residents to vote for the Conservative candidate in the Devon constituency of Torbay as part of their national campaign for the 2015 general election.
The cost of the leaflet drop was registered under the party's national campaign budget, but Mr Sanders argues it should have fallen under the local election spending budget - a much smaller limit.
Probes into the Conservative Party have already been launched by other police forces across the country, focusing on whether the Tories breached spending rules ahead of their knife-edge poll win last year.
Mr Sanders, who lost his seat to Conservative Kevin Foster, said of the leaflet on BBC Radio 4's Today show: "It's not a general leaflet, it is a specific targeted mailshot to a voter in a given constituency saying 'vote for our candidate in that constituency'.
"That has to be a local cost, not a national expense."
A spokesman for the Conservative Party said the leaflets made no reference to Mr Foster and were therefore not a local election expense.
He said: "Simply referring to the location where the elector lives does not promote any named candidate.
"The literature only promoted the national Conservative Party."
Devon and Cornwall Police are already investigating other alleged breaches of spending rules along with the Greater Manchester, Cheshire and Leicestershire police forces.
They centre on claims that the Tories listed the costs of bussing activists into key marginal seats under national, rather than local, spending accounts.
The party acknowledges that some accommodation for the activists was not properly registered, but insists that the bus tour was part of the national campaign organised by Conservative campaign headquarters (CCHQ) and as such did not fall to be recorded in individual constituency spending limits.
On Thursday, the Conservative Party handed evidence regarding the spending controversy to the Electoral Commission.
The probe has already led to calls for the new Police and Crime Commissioner (PCC) for Devon and Cornwall to stand aside while she is investigated over her part in the campaign.
Alison Hernandez, who was elected PCC last week, was the Conservative agent, responsible for reporting local expenses.
West Midlands Police became the latest force to confirm it is looking into allegations surrounding the election.
Detective Chief Inspector Ed Foster said: "We have received an allegation of improper electoral campaign spending returns in the West Midlands area and are reviewing whether any offences have been committed.
"We will be applying for an extension on time to investigate and continue to liaise closely with the National Police Chiefs Council and the Electoral Commission."