Police have launched an investigation into secret recordings made by a Welsh assembly member of the man who oversees complaints about AMs.
Independent AM Neil McEvoy claimed his recordings of standards commissioner Sir Roderick Evans revealed sexism and bias.
Sir Roderick, who resigned on Monday, said much of what had been shared was out of context and misleading.
Mr McEvoy’s actions prompted a security sweep of the assembly estate.
South Wales Police said it had “commenced an investigation following a referral from the National Assembly for Wales concerning allegations of covert recordings”.
Mr McEvoy – who was facing three separate investigations by Sir Roderick – has been asked to comment.
Opening assembly business on Tuesday, presiding officer Elin Jones said police had been asked to look into how the recordings were made and investigate their legality.
“The covert recording of private conversations on the assembly estate is a serious breach of trust,” she said.
She alleged the recordings included confidential evidence by a witness during an investigation into Mr McEvoy’s conduct.
Assembly authorities have begun the process of finding a new commissioner and Ms Jones told the assembly no complaints would be dropped as a result of Sir Roderick’s resignation.
Mr McEvoy defended his secret recordings of Sir Roderick and his staff in a press conference on Tuesday.
Accusing Sir Roderick of presiding over a “locker room culture”, he claimed the commissioner aired “really sexist views” about “female lawyers who – of course because they’re female – they’re emotional”.
He added: “There was a provocative and politically incorrect culture in the commissioner’s office that came across through the recordings.”
Mr McEvoy alleged he heard a joke made about women politicians and a comment that former Plaid Cymru leader Leanne Wood should “wind her neck in”.
Sir Roderick, a former high court judge and pro-chancellor of Swansea University, previously said Mr McEvoy’s conduct was “wholly unacceptable” and “undermines the integrity of the complaints procedure”.