The Welsh Tories have said they are "deeply sorry" for the circumstances around a collapsed rape trial involving a former aide to Alun Cairns.
Ross England caused the case's collapse when he gave evidence a judge had ruled inadmissible.
Eight months later he was selected to stand for the Conservatives in the 2021 Welsh Assembly elections.
A spokeswoman said the party was sorry for the distress caused to the victim at the centre of the trial.
A row over what Mr Cairns knew about the collapse of the court case led to his decision to quit as Welsh secretary on Wednesday.
The defendant James Hackett, a friend of Mr England's, was subsequently convicted of rape at a retrial.
On Thursday morning Lord Davies of Gower, who has been the chairman of the party in Wales since 2017, said he "deeply regrets" the situation has arisen but added: "There will be an apology if I find out that one should be forthcoming."
Following the interview a statement was sent to BBC Wales in which a party spokeswoman said: "We are deeply sorry for the circumstances surrounding the collapse of the trial and the deep distress this must have caused the victim, her family and friends.
"Mr England has been suspended from the party and a full investigation is under way.
"We are proud to support the many women who work for or engage with our party and employ a strict ethical code for staff and volunteers as part of our human resource strategy."
In evidence to the April 2018 trial Mr England made claims of a casual sexual relationship with the victim, which she has denied.
The judge Stephen John Hopkins had earlier told the trial that evidence of the sexual history of the victim was inadmissible.
He told Mr England: "You have managed single-handed, and I have no doubt it was deliberate on your part, to sabotage this trial… get out of my court."
Mr Cairns, the Conservative general election candidate for the Vale of Glamorgan, had claimed he did not know about Mr England's involvement in the collapse of the trial until last week.
He resigned from the cabinet after BBC Wales obtained an email from August 2018 that had been sent to him discussing the case.
In his resignation letter Mr Cairns said: "I will co-operate in full with the investigation under the ministerial code which will now take place and I am confident I will be cleared of any breach or wrong doing."
David TC Davies, the party's candidate for Monmouth, said he did not believe Mr England should be eligible to stand as a candidate for the Welsh assembly elections.
Other candidates standing in the Vale of Glamorgan include Belinda Loveluck-Edwards for Welsh Labour and Anthony Slaughter for the Wales Green Party.
The close of nominations is 14 November.