The former Dyfed-Powys Police chief constable sent private e-mails at work about a personal relationship, it has been confirmed.
Terry Grange had been chief constable for seven years
Terry Grange, 58, retired from his post on Monday amid allegations of misuse of a police computer and financial irregularities.
Dyfed-Powys Police Authority has now clarified that the computer allegation related to private e-mails.
It said the e-mails contravened force policy on computer use at work.
Following Mr Grange's retirement, the Independent Police Complaints Commission (IPCC), which is investigating, said the computer claim no longer applied to its probe into the allegations because it was a conduct issue covered by police regulations.
But the claim of financial irregularities against Mr Grange is still being examined by the IPCC.
If there is enough evidence, a file could be submitted to the Crown Prosecution Service.
In a statement issued on Wednesday, Dyfed-Powys Police Authority said: "Dyfed-Powys Police Authority has become aware of rumours concerning the allegation of computer misuse by its former chief constable Mr Grange.
"Following consultation with the IPCC the police authority would wish it to be clarified that this relates to private e-mails concerning a personal relationship entered into by the former chief constable with a person unconnected with either the Authority or the Dyfed-Powys police force.
"Such personal use contravenes force policy on computer use within the workplace."
Meanwhile, members of Dyfed-Powys Police Authority will meet in private later for the first time since the sudden retirement of their chief constable.
It will be the first opportunity all 19 members will have had to discuss the departure of Mr Grange.
An emergency committee of five members of the authority met on Monday to discuss the allegations facing Mr Grange, hours before he stepped down.
Several politicians have voiced concern about the circumstances of the departure, with calls that the investigation is carried out with transparency.
Mr Grange became Dyfed-Powys chief constable in 2000.
As a member of the Association of Chief Police Officers (Acpo), Mr Grange held the organisation's personal crime portfolio and was its spokesman on child protection issues.
In that role he has given evidence to MPs on their inquiries into police investigations of institutional child abuse.
He was also known for his tough line on illicit drugs.