Questions have been raised over the appointment of the assistant chief constable of South Wales Police.
While working for Merseyside Police, Nikki Holland was given the job of leading an investigation into the Welsh force's role in a miscarriage of justice.
Three men from Cardiff spent a decade in jail after being wrongly convicted of killing newsagent Phillip Saunders in 1987.
Plaid Cymru MP Elfyn Llwyd has written to the Home Secretary asking if it was appropriate that Ms Holland was given the job as the report into the case she led has not yet been published.
Mr Llwyd said he is 'rather concerned' about the situation.
Deputy Chief Constable Matt Jukes of South Wales Police said:
“Following a thorough and robust investigation, this work was completed in April 2012 around two years before Ms Holland applied for her current position.
"In November 2012, the CPS independently reached the conclusion that there was insufficient evidence to bring charges against anyone in this matter."