The leader of the Reform UK group on Huntingdonshire District Council has been arrested on suspicion of making false statements in nomination papers for May's elections.
Ryan Coogan was elected to represent the Ramsey ward on 7 May, when Reform became the authority's third-largest party.
Cambridgeshire Police said a 42-year-old man from Waterbeach was arrested on 24 September on suspicion of making false statements in nomination papers.
He has been released on bail and must return to Milton Police Station on 22 December.
Mr Coogan said he had not been informed of the details of the allegation.
A Huntingdonshire District Council spokesperson said the matter was an ongoing police investigation and it would not be appropriate for the council to comment further at this stage.
