The watchdog said it was also investigating whether there had been a failure to disclose information that may have helped Mr Malkinson at his trial and it was also looking at whether officers followed the “appropriate processes” in how Mr Malkinson had been identified.
The watchdog said it was also investigating how GMP handled and disposed of evidence.
During Mr Malkinson’s successful appeal last year, it emerged that the original DNA samples recovered from the victim and her clothing had been destroyed.
Catherine Bates, IOPC Regional Director, said: “Mr Malkinson is a victim of one of the worst miscarriages of justice in British history.
“Following a detailed review of evidence spanning a period of more than 20 years, we have now informed four retired GMP officers that they are under investigation for potential gross misconduct.
“One of the officers has also been notified that they are under criminal investigation for potential misconduct in public office and perverting the course of justice in relation to their actions during the police investigation and subsequent trial.
“We will continue to keep Mr Malkinson and GMP updated on our progress.”
