GREATER Manchester's chief constable and two senior officers are being investigated over claims an investigation was "poorly handled".
Ch Con Peter Fahy, as well as a detective superintendent and a detective chief inspector, have been issued with criminal and misconduct notices informing them their actions may have breached their standards of professional behaviour.
Ch Con Fahy's alleged involvement is realted to support that is said to have been given during the investigation.
The investigation has been launched by the Independent Police Complaints Commission (IPCC) after a whistleblower within the force raised concerns about multiple allegations.
A retired police officer has also been issued with a notice.
Three of the four have been told they are under criminal investigation.
The allegation relates to a "poorly handled investigation into a suspected sex offender".
Another senior officer, Ass Ch Con Terry Sweeney, has also been served with a gross misconduct notice for his oversight role in the disposal of body parts belonging to victims of the serial killer Harold Shipman.
The whistleblower has been interviewed by the IPCC.
Ch Con Peter Fahy said: "As a chief constable you face making complex decisions on a daily basis about many high risk and challenging situations.
"It is right that this decision-making is scrutinised and that I am held to account as part of this investigation."