The Independent Police Complaints Commission is investigating the involvement of the Freemasons in the Hillsborough disaster and subsequent cover-up, it has revealed.

The watchdog is examining whether senior police officers’ membership of the secret society had a bearing on the events that led to 96 people losing their lives at Hillsborough stadium in Sheffield, during a football match between Liverpool and Nottingham Forest in April 1989.

Fans were crushed to death after too many supporters were allowed onto the terrace, with numerous policing failures having since been blamed.

Both Former Chief Superintendent David Duckenfield, who had overall responsibility for policing at the match, and his predecessor Brian Mole were members of the Freemasons. Mr Duckenfield became Worshipful Master – the head of his local lodge – the year after the disaster.

The links came to light during the latest inquests into the deaths, which ruled the victims were unlawfully killed. During questioning by lawyers representing the victims’ families, Mr Duckenfield confirmed he was a member of the Freemasons and had been at the time of the tragedy for around 14 years.

But he denied it was likely to have been a factor in his promotion to Chief Superintendent, saying “I hope not”.

The inquest dwelled on why Mr Duckenfield was promoted to a position he appeared to be under-qualified for, with responsibility for a large policing operation on the day of the match.

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In the latest update on its investigation into alleged criminality following the tragedy, IPPC deputy chair Rachel Cerfontyne said in a statement: “We are pursuing a further line of inquiry on Freemasons.

“We are currently liaising with the United Grand Lodge of England, and they are assisting us by checking whether certain individuals involved in Hillsborough were Freemasons members.”

The IPCC told The Independent enquiries into Freemason links remained one of their outstanding investigative strands, which they hoped to complete along with the rest of their enquiries by the end of the year.

The analysis of the relationship between the Freemasons and South Yorkshire police officers relates purely to historical links, with no suggestion that serving officers are being investigated.

A spokesman for the United Grand Lodge of England confirmed they were assisting the IPCC with their investigation.

He told The Independent: “United Grand Lodge of England continues to assist with the Hillsborough investigation, as it has at every point, and where we might be useful.

“We have, from the start, welcomed the investigation and have urged all members to co-operate fully and openly.”

The spokesman confirmed the assistance given to the IPCC mostly related to enquires about membership status.

The latest inquest results were announced earlier this year after a 17-year campaign by the Hillsborough families on behalf of the victims. The IPCC’s findings will be passed to the Crown Prosecution Service to determine whether any of the police officers involved should face criminal charges.