Jeremy Newmark is at the centre of the "internal financial matters" referred to the police for investigation by the Jewish Labour Movement.
The JC has learned that allegations around Mr Newmark's conduct led to the decision made by senior figures within the JLM to call in the police.
Mr Newmark stepped down as chair of the organisation earlier this month, days after the JC revealed allegations of financial impropriety during his time at the helm of the Jewish Leadership Council five years ago.
One source confirmed to the JC this week: "The JLM decision to contact police does relate to Jeremy Newmark. There's nothing else I can say at this time."
Sources confirmed that City of London Police was dealing with the matter.
An email sent last Wednesday to JLM members written by national secretary Peter Mason said the organisation had "initiated an external review of our accounting and procedures, as well as taking legal advice."
Mr Mason added: "In order to ensure full transparency, openness, and to protect the integrity of the movement, we have referred certain internal financial matters to the police for investigation."
Mr Mason had earlier issued a statement reassuring members that there were no allegations against Mr Newmark during his time with the organisation, as JLM national officers had "full oversight of all processes".
Last Wednesday, the JLC announced an independent committee to lead its review of the allegations surrounding former chief executive Mr Newmark.
A retired judge will be appointed to chair the group.
The JLC is awaiting the Charity Commission's approval.
The JLC said last week it was beginning an in-depth review of its handling of Mr Newmark's departure from the organisation in 2013.
Mr Newmark has denied any wrongdoing during his time at the JLC, which he officially left on the grounds that he was suffering from diabetes.
A JLM spokesperson said on Wednesday that the group would be making no further comment on the decision to call in the police.
The orgainsation is expected to announce its plan to elect a new chair in the next few days.
