A former chief constable said he feared being jailed after he was accused of a child abuse cover-up.
Mick Creedon was a senior detective at Leicestershire Police during the 1990s when allegations into former Leicester MP Lord Janner were first investigated.
He described a historic inquiry into his professional behaviour in 2015 as being “like a witch hunt”.
Lord Janner, who denied all charges against him, died in 2015.
Mr Creedon has spoken out after the recent Independent Inquiry into Child Sexual Abuse (IICSA) heard he was ordered not to arrest Lord Janner, “despite credible evidence”.
The inquiry, which is due to publish its findings in 2021, was not set up to determine Lord Janner’s guilt or innocence but to look at how authorities reacted to multiple allegations dating back decades.
Mr Creedon, who became chief constable of Derbyshire Police in 2007, said allegations against him appeared after he voiced concerns his investigation into Lord Janner had been halted on orders from above.
“I was stunned. It had a huge effect on my family, my marriage, my friendships and it tends to take over,” he told the BBC.
“Because at the end of the day the offences which I was being investigated for carry life imprisonment.
“It felt to me like a witch-hunt. I was treated like a corrupt officer.”
His barrister branded a subsequent investigation into Mr Creedon years later by the Independent Office of Police Conduct (IOPC) as “amateur” and “irrational”.
He said Mr Creedon was the victim of “malicious rumours, myths and outright lies”.
“I was a respected chief constable and I think they saw me as a target,” he added.
He was among several police officers referred by Leicestershire Police over complaints of unprofessionalism over the Janner inquiry.
“I believe it was a vindictive response. Within four to five weeks they gathered a range of information about me – all of which has since proved to be false,” he said.
“One was a statement with an admission they knew I didn’t take, and one was an operation into Janner that I wasn’t involved with, where I was accused of being the decision maker.
“It was utterly, utterly crazy.”
The IOPC investigation lasted four years but found no evidence to take action against the officers.
The IOPC denied the criticisms and called the investigation “complex”.
A Leicestershire Police spokeswoman added: “Where concerns were highlighted about previous investigations into allegations made against Lord Janner, the force took the view that where it appeared the conduct of officers may have fallen below the standards of professional behaviour, referrals would be made to the IOPC.”
She said involving the police watchdog allowed the force to remain independent and transparent.