Mike Veale, who leads Wiltshire Police, has written an open letter to the public to "set the record straight" about the investigation into child sex allegations against former prime minister Sir Edward Heath.
The police probe, named Operation Conifer, began in 2015 after claims against Heath surfaced.
"When I took on this investigation I knew it would attract intense scrutiny. I also recognised it could potentially damage confidence in Wiltshire Police," Veale said.
Veale described the investigation as "complex and multi-stranded" but added: "This is not a 'fishing trip' or 'witch-hunt' - both of these terms have been unfairly levelled at us.
Last weekend The Mail On Sunday reported the contents of a leaked confidential report into Operation Conifer, which referred to satanic ritual sex abuse.
"Let me be clear, this part of the investigation is only one small element of the overall inquiry and does not relate to Sir Edward Heath," Veale said.
"It is also very important for me to reiterate that the report forms part of a live ongoing criminal investigation, so the disclosure of this information is something which we take very seriously."
The Independent Police Complaints Commission launched a probe into alleged historical corruption after information from a retired officer raised concerns that Wiltshire Police deliberately caused a criminal prosecution to fail 22 years ago.
Earlier this year the probe found no evidence that a prosecution against a brothel keeper was dropped because of threats to allege publicly that Heath had been involved in sexual offences.