The SNP has reacted angrily to claims it was warned about MSP Bill Walker three years before he became an MSP.
A relative of Mr Walker, who was convicted of 23 domestic abuse charges, said he approached the party about his violent conduct in 2008.
Rob Armstrong, the brother-in-law of the MSP's third wife Diane, said he handed documentation to Nicola Sturgeon's parliamentary office.
But the deputy first minister said she was not aware of the information.
She described Mr Walker as a "vile man" but said it was a party issue - not a constituency matter - and a member of staff passed the information to SNP headquarters.
She added: "As my staff are not employed by the SNP, these matters are quite rightly passed on to the party. The member of staff who spoke to Mr Armstrong acted absolutely appropriately.
"The investigation conducted by a member of staff at SNP HQ did not find any evidence of any complaint in law or legal proceedings into domestic violence by Mr Walker, and the inquiry was then closed.
"However, changes have since been made to our internal procedures in light of the Bill Walker case to ensure that in future any relevant information about a potential candidate - whether backed by hard evidence or not - is passed to the Election Committee."
Walker won Dunfermline for the SNP in 2011, but was expelled by the party after the abuse allegations emerged.
The SNP said inquiries in 2008 found "no evidence of any complaint in law".
Walker remained as an independent MSP but has now been urged to stand down.
The 71-year-old, from Alloa, was convicted of attacking three former wives and a stepdaughter between 1967 and 1995.
He will be sentenced on 20 September, but would only be disqualified as an MSP if he was jailed for more than a year.
Mr Armstrong told Newsnight Scotland he had seen a member of staff at Nicola Sturgeon's office in early February 2008 and expressed concern that Walker was a councillor.
"I felt that there was certain detail with regard to this man's past which I felt they should be aware of," he said.
Mr Armstrong said he told the office about instances of violence and gave them affidavits provided by Walker's former wife and stepdaughter.
He also said he provided a court judgement with a penal notice attached which Mr Armstrong said threatened Walker with prison if he exerted violence or chastisement towards a named child.
He said the SNP staff member had photocopied newspaper items - one of which he said detailed the level of violence exerted towards his stepdaughter, as well as his second wife, and an incident with his third wife.
"Even in that article there was sufficient indication of the violent nature of the man's character," Mr Armstrong said. "There was sufficient evidence for it to have gone to some sort of inquiry."
Mr Armstrong said no-one from the SNP got in touch with him following the meeting.
"I thought it was a blatant disregard for something that was exceedingly important," he said.
The SNP has said "reasonable inquiries" were made into the allegations.
A statement from the party said: "Under the SNP's rules, it was Mr Walker's inescapable responsibility to inform the party's candidate assessment panel of information that has come to light, which he completely failed to do, and of course he even denied in a court of law.
"The matter was considered by a member of staff at SNP headquarters and reasonable enquiries made, but there was no evidence of any complaint in law or legal proceedings into Mr Walker's conduct, and the inquiry was closed."
Ms Sturgeon added: "It is, of course, the case that knowing what is now known about Bill Walker, we all wish that he had been prevented from becoming an SNP candidate.
"The fact is that Bill Walker is the guilty party here. He has no place in public life and he should do what every right-thinking person wants him to do and stand down from parliament."