The brother of a man convicted but then pardoned for the Crewe double murders has questioned why a police investigation has taken so long.
Arthur Allan Thomas was convicted but later pardoned of the murders of Harvey and Jeanette Crewe in 1970.
Des Thomas has laid a formal complaint with the Independent Police Conduct Authority against the Police Commissioner, Peter Marshall.
He laid an initial complaint with police in 2012 against the actions of the former detective Bruce Hutton, but said he believes the police delayed an investigation until after Mr Hutton's death last year.
Des Thomas says a proper independent inquiry is needed.
The police said Mr Thomas's complaint was still being considered by a review team and they hoped the findings would be made public in the first half of this year.