South Yorkshire Police, Sheffield Wednesday Football Club, Sheffield City Council and the Football Association are being investigated for possible criminal culpability over the Hillsborough disaster.
The disclosure was made by the senior detective leading an investigation into the tragedy, when 96 people died at the stadium in Sheffield on 15 April 1989.
Jon Stoddart, former chief constable of the Durham force, told the Guardian that all four organisations were being investigated for possible gross negligence manslaughter.
He said: "We are exploring all liability, both public and individual. We are looking at unlawful killing; who is responsible for the deaths."
He said more was being looked at than command and control of the crowd.
"It is about the safety of the stadium, certification, the planning and preparation, the engineering and design" - Jon Stoddart
"It is about the safety of the stadium, certification, the planning and preparation, the engineering and design that went into the Leppings Lane end [where the people died]."
The club offered to host the match despite serial breaches of the Home Office guide to ground safety and a safety certificate ten years out of date, the newspaper said, while the council was statutorily responsible for licensing the stadium as safe, and the FA commissioned the ground for the FA Cup semi-final despite Hillsborough's safety breaches and previous crushes at semi-finals there in 1981, 1987 and 1988.
Meanwhile, it has emerged that more than 90 police pocket notebooks that could contain crucial new information about the disaster have been recovered by investigators.
The Independent Police Complaints Commission (IPCC), which revealed last month that it was looking for the notebooks, said 90 had been handed in to South Yorkshire Police by retired and serving officers.
The force has also found boxes of notebooks and other documents that cover the period of the disaster, which could contain vital details.
Deputy chairwoman of the IPCC, Deborah Glass said: "This is an ongoing criminal investigation the like of which has never been seen before in this country. Already we are uncovering more about the disaster and its aftermath.
"Hillsborough has had a history of inquiries by the police and others, many completed quickly, coming to flawed conclusions. Our investigations need to deliver the last, definitive account."
Last month the IPCC revealed that at least at one officer made a note of what happened that day, against instructions, and that none of the previous inquiries into the tragedy had recovered any such notebooks.
The disaster is now at the centre of the biggest ever inquiry into police conduct in the UK.
The IPCC said it has uncovered evidence to suggest that the statements of 74 more officers might have been changed, and that fans' witness accounts could also have been altered.
Investigators are set to appeal for witnesses next week in relation to how West Midlands Police ran their inquiry into the handling of the disaster by South Yorkshire Police.
Around 12,000 people spoke to West Midlands Police during the inquiry.