Evidence existed to prosecute Emma Caldwell murderer Iain Packer in 2008, the family’s lawyer has said after they met Scotland’s top law officer.

Packer, 51, was sentenced to life with a minimum term of 36 years at the High Court in Glasgow last week after being found guilty of murdering the 27-year-old in 2005, as well as 11 rapes and 21 other charges, including sexual assaults, against other women.

Miss Caldwell’s mother Margaret met Lord Advocate Dorothy Bain KC at the Crown Office in Edinburgh on Thursday, ahead of an announcement of a public inquiry into the botched investigation of her daughter’s murder.

Speaking outside the Crown Office following the meeting, the family’s lawyer Aamer Anwar said: “The Lord Advocate confirmed that had the solicitor general and her instruction been followed through by Strathclyde Police, on the available evidence in 2008 the Lord Advocate and her team believe there was a sufficiency for prosecuting Iain Packer for murder.

“The Lord Advocate apologised today and said the Crown Office should have done more and failed to do so after 2008.”

Mr Anwar said Ms Bain and the then solicitor general asked Strathclyde Police to re-investigate the case using new officers in 2008, but it was “impossible to work out what happened after that instruction was given”.

He accused the police of a “cover up” and said “criminality has never been fully investigated by Police Scotland”.

Ms Bain said she is taking advice on instructing an external police force to investigate the actions of police.

Police Scotland said they “fully support any further police investigation”.

Mr Anwar said: “Today the family paid tribute to the Lord Advocate Dorothy Bain KC and her prosecution team who have been unwavering in their commitment to justice, without her leadership, the work of the Crown Office and the present police murder team, justice would have been buried forever.”

Ms Bain said: “Margaret Caldwell and her family suffered an unimaginable loss which was compounded by a painful wait to see Emma’s memory honoured through justice being done. I have been humbled and inspired by the family’s commitment to shining a light on what happened.

“In my meeting with the family I apologised to them for the prosecution service not doing more sooner. Emma, and all of the women harmed by Packer, deserved better.

“With respect to criminal actions of police, I am taking advice on instructing a force from outside Scotland to look further at allegations against officers.

“As previously stated, the Crown has reserved its position in relation to potential proceedings should evidence in support of those become available.”

She said the way Police Scotland and the Crown Office work together has been “transformed” in recent years and “allegations of violence against women are heard and acted upon”.

Mrs Caldwell and the family met Police Scotland Chief Constable Jo Farrell on Wednesday, and the officer apologised to them and the families of Packer’s other victims for having been “let down by policing in 2005” and backed calls for an inquiry.

She said: “We have reflected and learned from the initial investigation and subsequent re-investigation. Significant changes have been made to improve organisational culture and response, particularly in respect of investigative structures, victim care and processes to these types of crimes.”

A Police Scotland spokesperson said on Thursday: “The Chief Constable met Emma Caldwell’s family earlier this week and personally apologised for the failings of policing.

“We are aware of announcements today by both the Scottish Government and the Lord Advocate.

“We will fully support the public inquiry and any further police investigation.”

Miss Caldwell’s family met First Minister Humza Yousaf and Justice Secretary Angela Constance earlier in the week.

Packer is appealing against his conviction and sentence.