Opposition politicians have joined forces to back the family of a murdered father of three who are seeking answers to “legitimate and series questions” surrounding his killing.

The family of Craig McClelland insist there should be a inquiry into the circumstances of his death in July 2017.

The 31-year-old was stabbed to death in his home town of Paisley by James Wright, who had previously been released from prison on an electronic tag, and at the time of killing was “unlawfully at large”.

First Minister Nicola Sturgeon has described his murder as “awful” and said she was not surprised the family is still seeking answers.

While both police and prison inspectors carried out reviews of systems following the incident, the family said these failed to fully explain why his killer was out on the streets.

Conservative justice spokesman Liam Kerr, his Labour counterpart Daniel Johnson and Scottish Liberal Democrat leader Willie Rennie all met Mr McClelland’s partner Stacy and his father Michael.

Afterwards the three politicians sent a joint letter to Justice Secretary Humza Yousaf, calling for a fulling independent inquiry to be conducted into the circumstances of the killing.

They told him: “We welcome your personal commitment to ensuring lessons will be learned but it is impossible for this to be done until there is full transparency about what occurred.

“There is no such transparency at present.”

The politicians added “something clearly went wrong” within the system to allow for Wright to be free to commit the murder, and said it was “incumbent” on the Justice Secretary to establish what this was.

They said: “There must be clarity about the circumstances, in particular the grounds and process for releasing James Wright in the first place and how he was allowed to be unlawfully at large when he broke the rules and should have been returned to prison.

“Craig’s family deserve to know and we believe that an inquiry would also undoubtedly be in the public’s interest. As Stacey put it, Craig was by dreadful chance the victim but it could have been anyone.

“We urge you to immediately order a full independent inquiry. Without this, nobody can be assured that the solutions proposed will stop such an appalling series of events happening again.”

Home Detention Curfews (HDCs) have been used in Scotland since 2006, and allow for prisoners to serve part of their sentence in the community while being monitored via an electronic tag.

Scottish Prison Service chief executive Colin McConnell told MSPs on Tuesday that a presumption against HDCs for those convicted of violent offences – which has been brought in following the reviews – had reduced the number of prisoners freed in such conditions from 25 to 30 a week to just seven.

Justice Secretary Humza Yousaf said: “While nothing can take away the grief of the McClelland family, the Scottish Government will continue to do all we can to support the family to ensure that lessons are learned and improvements are made. I will reply to the letter as soon as possible, and will be meeting the family again shortly.

“Following the publication of the two independent inspectorate reports into the Home Detention Curfew scheme, I met with the family and advised that the Scottish Government, the Scottish Prison Service, and Police Scotland had accepted all of the reports’ recommendations, including considering making it a specific offence to remain ‘unlawfully at large’.

“Our focus is on ensuring that relevant agencies, along with government, make real and demonstrable progress and I have asked both Inspectorates to review progress in six months’ time.”