Explosive new allegations of vote rigging in Tower Hamlets are expected to be submitted to Scotland Yard later today.
Detectives are already investigating 16 claims involving postal votes and election leaflets ahead of Thursday's re-run election.
Further allegations are expected to be made today when a dossier is handed to Met Commissioner Sir Bernard Hogan-Howe.
The ballot was triggered by a court case which ruled the 2014 election of Tower Hamlets mayor Lutfur Rahman was riddled with corruption and intimidation.
Muslim candidates were told it was 'un-Islamic' to vote for another candidate, Bangladeshi groups were 'bribed' with council grants and a rival candidate was smeared as a racist.
Rahman was ejected from office and banned from standing in an election for five years.
His party, Tower Hamlets First, is no longer recognised by the election watchdog.
A former Tower Hamlets First councillor, Rabina Khan, who was 'anointed' by Rahman as his successor, is standing as an independent.
A blogger claims he filmed an official from the council's housing agency distributing official leaflets with Khan election literature 'tucked inside'.
Khan released a statement denying any involvement.
Anti-corruption campaigner Andy Erlam, who is also a candidate, plans to submit 'new files of evidence of election fraud and financial fraud' to the police later today.