The Crown Prosecution Service has confirmed that Kent Police passed it a file on allegations concerning Conservative general election expenses in South Thanet in 2015.
Kent Police met the CPS to discuss the matter in March but at the time there were no formal dossiers handed over.
The CPS, which says it received the file recently, will now review the evidence before deciding whether any charges should be brought.
They will have until early June to do so under election rules which state that any charges must be brought within 12 months of an inquiry starting.
The timing of any charge may be made in the same week of the general election itself which takes place on the 8 June.
Candidates standing in the South Thanet constituency could spend £15,087.30 in an election period between 9 April and May 7 2015.
The seat was eventually won by Conservative Craig Mackinlay who beat Ukip's Nigel Farage by just over 2,500 votes.
Mackinlay was questioned by Kent Police for six hours over alleged overspending in the campaign.
The allegations concern claims that the Conservative Party failed to properly report its election expenditure in the campaign in South Thanet.
The claims are said to include queries over the Tories 2015 "battle bus" which toured the country. The allegations centre on whether spending on hotels for visiting activists and certain campaign material was incorrectly registered as national spending rather than locally – potentially illegitimately taking advantage of a higher spending ceiling.
Several other constituencies are also being looked into by the CPS after multiple police forces handed over files with queries over election expenses from 2015.
The Conservative Party was recently fined a record £70,000 for irregularities in its election expenses including money spent fighting for South Thanet.
This was in a separate investigation conducted by the Electoral Commission, the election watchdog, concluded that there were significant failures by the party to report accurately how much it spent campaigning at three by-elections in 2014 and at the 2015 UK Parliamentary general election.