The Liberal Democrats are facing a police investigation over allegations that they received donations in breach of party funding rules.
The Electoral Commission said that it had passed details of the alleged breaches to the Metropolitan Police as they were potentially a "criminal matter".
The allegations relate to recent reports by The Daily Telegraph and the Channel 4 Dispatches programme.
A Liberal Democrat spokesman said: "When the party was notified of the allegations, we immediately referred them to the Electoral Commission and have fully complied with their inquiries.
"We will continue to cooperate with any investigation."
The Electoral Commission said that in each case the alleged offences referred to the potential evasion of restrictions under Section 61 of the Political Parties, Elections and Referendums Act (PPERA).
"Offences under this part of PPERA are ultimately a criminal matter and fall outside of the commission's civil sanctioning powers," the commission said in a statement.
"The Electoral Commission has therefore passed the information that it has received to the Metropolitan Police Service (MPS). The MPS have confirmed to the commission that they are also aware of the allegations and that they are considering them."
The Telegraph allegations relate to the Lib Dems' former chief fundraiser Ibrahim Taguri who was filmed apparently advising an undercover reporter on how he could circumvent the rules on declaring donations by making it through "a cousin".
In the Dispatches report the Lib Dem peer, Lord Strasburger, was shown apparently advising businessman Paul Wilmott, posing as a potential backer with up to £50,000 to donate, how he could channel gifts through his "stepfather".
The Electoral Commission said that the party had received and accepted a donation of £1,450 in the Telegraph case and one of £10,000 in the Dispatches case.
"The commission is in contact with the Liberal Democrats about the actual source of these donations and will provide a separate statement about this matter once these further facts have been established," it said.
A further cheque for £7,650 was delivered to the party in the Telegraph case, but because it had not been banked no offence had been committed under the PPERA.
The Metropolitan Police confirrmed that it was liaising with the commission regarding "possible irregularities in relation to political party donations".
"There are two matters currently subject to assessment by officers from the special inquiry team," a spokesman said.