Spotlight: Research Services Ireland got £700,000 in Sinn Féin expenses
Sinn Féin MLAs have claimed nearly £700,000 in expenses for research from a company run by the party's finance managers.
The revelations came in a second BBC Spotlight programme on MLAs' expenses.
The programme also found claims of more than £4,000 in heating oil costs for one DUP MLA's office.
One MLA has called on police to investigate what he described as "several aspects of what appear to involve criminality".
Traditional Ulster Voice leader Jim Allister said he would be writing to the chief constable about the issue.
"In particular, the siphoning of public money by Sinn Fein to an apparently bogus research company must be thoroughly investigated, along with potential forgery," he said.
Over the past 10 years, 36 different Sinn Féin MLAs claimed about £700,000 in total through Stormont expenses to pay Research Services Ireland.
Martin McGuinness alone claimed £42,000 over 10 years for the expertise of the company.
The company is run by Seamus Drumm and Sinead Walsh, who are in charge of running Sinn Féin's finance department in Northern Ireland.
The BBC Spotlight NI programme was not able to find any evidence of research that had been carried out by Research Services Ireland (RSI).
The party said that RSI provided a centralised service and that other research facilities could not be used because the work was "too sensitive".
One Sinn Féin MLA said they had never heard of the company until they saw it on their annual expenses.
Five years ago, the police were alerted to concerns about expenses claims made by Sinn Féin for work done by the company, and a meeting was held with two assembly officials.
At the time, the Police Service of Northern Ireland decided that an investigation was not necessary.
Sinn Féin's biggest claims for payment to Research Services Ireland came after that date.
The party said that its office cost allowance spent with RSI was used exclusively for assembly and constituency work.
Speaking on the BBC's Nolan Show, Sinn Féin MLA Raymond McCartney said there had been "no impropriety" in his party's expenses claims and added they had "nothing to hide".
"I have no issue with any investigative process, indeed the Spotlight programme alluded that some time in the past the PSNI had been involved.
"They didn't find anything to proceed with an investigative process, I can draw a conclusion from that there was no evidence to go by" Mr McCartney said.
The former chair of the Westminster Committee on Standards in Public Life, Sir Alistair Graham, believes the issue should interest police.
"That sounds to me very near fraud - fraudulent behaviour and I would have thought was a very clear breach of even the current rules in Northern Ireland," he said.
"And I would've thought was worthy of police investigation."
Meanwhile, £4,355 was claimed in one year in the name of the former assembly speaker and DUP MLA Willie Hay for his constituency office's heating oil - the cost of heating his offices increased from £265 over a 10-year period.
Mr Hay's brother-in-law and former office manager has been suspended since Spotlight raised the issue with Mr Hay.
The former speaker now says he cannot comment on the issue as it is now the subject of a police investigation.
The heating oil company who were named as the recipients of the claim told Spotlight that they had not yet been contacted by the police about the issue.
Each MLA is required to sign their own expenses claim forms. But one former Sinn Féin MLA said one expenses claim form for mileage was signed without his knowledge.
Davy Hyland was the Sinn Féin MLA for Newry and Armagh between 2003-2007 before being deselected by the party.
He does not drive and said that the only mileage he would have accrued would be the journey to and from Stormont, where his wife gave him a lift.
Spotlight obtained a copy of an expenses form claiming for 11,500 miles at a cost of almost £5,000.
Mr Hyland told the programme that shortly after he was deselected by the party and became an independent MLA, he received a phone call from the assembly finance team asking him to verify this mileage claim, of almost £5,000, which was about to be paid into Sinn Féin's bank account in west Belfast.
He told them he knew nothing about most of the mileage claimed.
Mr Hyland claimed the form had been signed without his knowledge. He also claimed a senior member of Sinn Féin's finance team then rang him and asked him to agree the expenses.
He said he refused, the claim was never processed, and the money was never transferred into the Sinn Féin bank account
The assembly told Spotlight the claim was never paid out and the assembly's bribery and fraud response plan was initiated.
Sinn Féin said they had no record of such an expenses application, and their records show no monies were drawn down on any such claim.
Mr Hyland was in the assembly for four years. In that time £19,000 was claimed in his name for mileage.
Mr Hyland said he did not use the bulk of the £19,000 of mileage claimed and he would not have knowingly signed off that amount.
Questions were also raised in the programme about Ulster Unionist and SDLP expense claims for services provided by their own parties.
The SDLP claimed £10,000 for each MLA to fund their press office. The rules say the money should have been going to benefit constituents.
The party said "any monies claimed for secretarial expenses or professional advisors… was spent to enhance the service given to constituents".
In one year the UUP claimed £84,000 for "support services".
Investigative Journalist Heather Brooke said these types of claim were "a way of taking money that the public's given to fund legitimate political expenses and it's recycling them into that political party".
Family members employed
The programme also found DUP MLAs employing a number of family members. Three quarters of all DUP MLAs have at least one relative on the pay roll, including eight wives, and eight sons.
Fifty-eight thousand pounds went to members of Robin Newton's family in 2013, who are employed in accordance with assembly rules.
With his own salary on top of that, a total of £106,000 from the assembly went into the Newton family in a year.
In recent years changes have been made to the way the expenses system operates. Money must now be paid to an MLA's individual bank account, rather than to a party account, as had been the case Sinn Féin.
However, Sir Alistair Graham believes that rather than just changing the system, people and parties should be held to account for past issues
"It seems to me that what you require here is a pretty root and branch independent investigation to the arrangements in place," he said.
"If there's potentially been a criminal offence or if there's been a serious breach of the rules, then I think there needs to be proper investigation."