The Independent Police Complaints Commission is revisiting its investigation into Lancashire’s Police and Crime Commissioner.
The move comes despite the Crown Prosecution Service announcing it will not prosecute Clive Grunshaw over allegations about his expense claims.
But the IPCC is carrying out “further investigatory work” after a complaint about its initial investigation into the expenses claims.
Last month Mr Grunshaw said he made “mistakes” in some of his expenses after the CPS cleared him of any criminal wrongdoing.
The CPS said in January there was “insufficient evidence” any claims had been “submitted dishonestly” and 28 none-claims “suggests” no financial gain was sought.
Mr Grunshaw became PCC in November 2012.