The head of the Metropolitan Police has condemned retired officers over their claims about finding pornography on Conservative Damian Green's computer.
Commissioner Cressida Dick said all officers had a duty to protect sensitive information they discovered.
She said the Met was investigating whether an offence had been committed and that there could be a prosecution.
First Secretary of State Mr Green denies watching or downloading pornography on his computer.
The allegations were first made last month by former Metropolitan Police assistant commissioner Bob Quick, who led a 2008 inquiry into Home Office leaks which saw Mr Green's Commons office being searched.
Mr Quick made his claims after the Cabinet Office launched an investigation into accusations of inappropriate behaviour by Mr Green towards journalist Kate Maltby, which the MP has described as "completely false".
And then on Friday, retired Met detective Neil Lewis said "thousands" of thumbnail images of legal pornography had been found on Mr Green's parliamentary computer in 2008.
Speaking on BBC Radio London, Ms Dick said: "All police officers know very well that they have a duty of confidentiality, a duty to protect personal information.
"That duty in my view clearly endures after you leave the service.
"And so it is my view that what they have done based on my understanding of what they're saying... what they have done is wrong, and I condemn it."
Officers come across sensitive information every day, the commissioner said, and "know full well" it is their duty to protect it.
She declined to give a "running commentary" on the Met's investigation - which is running parallel to the Cabinet Office probe - into whether confidential information has been disclosed.
She added: "I can say that we are reviewing...to see whether any offences have been committed."
Ms Dick told LBC there "could be a prosecution" but that this would be for the Crown Prosecution Service to decide.
BBC home affairs correspondent Danny Shaw said a prosecution under the Data Protection Act - which includes a public interest defence - was a possibility, although he added that things were at a very early stage.
The Met is currently reviewing the circumstances of the case and has not launched a full investigation, he added.