Police are assessing whether Reform UK candidates broke election spending rules.
The party has admitted making “administrative errors” during the Scottish Parliament election in May.
According to The Sunday Times and The Ferret, four Holyrood candidates have not submitted returns detailing how much they spent during their campaigns and the value of their donations.
Another five would-be MSPs who did submit returns reportedly failed to sign off on their spending properly, it has been reported.
A spokesperson for Police Scotland said: “Information has been received and is being assessed.”
Reform UK came joint-second with Labour at the Scottish elections in May, with both securing 17 MSPs.
None of the candidates who failed to declare their spending and donations were elected.
A spokesperson for Reform UK, which is led by Lord Malcolm Offord in Scotland, said: “These were simple administrative errors from a new party, with some seeking office and others behind the scenes very much learning the ropes.
“Each individual regrets not showing the necessary diligence and has since sought to rectify the situation by providing the requested information. Lessons have been learned.”
Last month, the Metropolitan Police launched a criminal investigation into claims senior figures in Nigel Farage’s party broke rules around foreign donations, following an undercover investigation by Channel 4 News.
And earlier this week, a separate undercover investigation by ITV News found candidates making racist and sexist remarks.
One would-be Reform UK MP told an undercover reporter Muslims could not be British and asylum seekers should be put in “concentration camps”.
Excerpts from the investigation released earlier in the week included councillors and candidates within Reform using racist language.
In one excerpt, black children were referred to as “animals”, while in another a Reform member said his area had become “infested” with Asian families.
In a separate clip, Reform MP Sarah Pochin described the party as “chauvinistic”, adding: “They just exclude you if you’re a woman.”
Speaking earlier in the week, Mr Farage said that while Reform carries out vetting “you can’t vet people for what they say in the future”.
He added: “I put it to you, if you went and spoke to hundreds of Conservative councillors and tried to provoke them you would find all sorts of things and all sorts of comments said.”
In a statement to ITV, Reform said: “Reform UK has improved and prioritised its vetting procedures, but from time to time, a handful of individuals who do not share our values will initially make it through vetting.
“This is the same for all organisations. However good the vetting, one cannot vet a future comment.
“There is no room for racism in Reform UK. We always respect due process of investigations and whilst these are ongoing it would not be appropriate to comment on individual cases.”
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