Hillsborough match commander David Duckenfield has been found not guilty of the gross negligence manslaughter of 95 Liverpool fans in the 1989 disaster.
The former South Yorkshire Police chief superintendent, 75, was in charge of the FA Cup semi-final in which 96 fans were fatally injured.
Men, women and children were crushed on the Leppings Lane terrace.
Mr Duckenfield, of Ferndown, Dorset, was cleared after a seven-week retrial at Preston Crown Court.
Due to the law at the time, there can be no prosecution over the death of the 96th victim, Tony Bland.
This is because he died more than a year and a day after his injuries were caused.
The jury at Mr Duckenfield’s original trial earlier this year failed to agree a verdict.
Christine Burke, whose father Henry Burke was killed in the disaster, stood in the public gallery and addressed the judge after the verdict was read out.
“With all due respect, my lord, 96 people were found unlawfully killed to a criminal standard,” she said.
“I would like to know who is responsible for my father’s death because someone is.”
Barry Devonside, whose son Christopher, 18, died in the disaster, said: “I’m shocked and stunned by the verdict of the jury.
“We, the families, have fought for 30 years valiantly.”
Paul Robinson, whose brother Steven was killed in the stadium crush, said: “As a family we would like to thank all those who have supported us over the years in our quest for justice and accountability.
“We firmly believe that we have done everything in our power to do right by our Steven and we walk away from this case with our dignity and our heads held high.”
Mr Duckenfield’s wife, Ann, went over to comfort her husband in the courtroom.
Judith Moritz, BBC North of England correspondent
The acquittal of David Duckenfield is the latest twist in the history of a disaster which has lasted 30 years. For all that time, the families of those who died, and the survivors of the crush, have campaigned for justice and accountability.
David Duckenfield has now stood trial 3 times. The first two juries – in Leeds 19 years ago, and in Preston earlier this year – were unable to reach verdicts. Now, at the third time of asking, a jury has made a clear decision about the Hillsborough match commander’s criminal liability.
He was charged with the gross negligence manslaughter of 95 Liverpool fans at an FA Cup Semi Final in Sheffield in 1989. Legally, the 96th victim, Tony Bland, could not be included in the prosecution as he died nearly 4 years later.
Mr Duckenfield did not dispute that he ordered the opening of a gate at Hillsborough to let fans in, or that he failed to close the tunnel to the terraces which were already full. In 2015 at the Hillsborough Inquests he accepted that this was the direct cause of the 96 deaths. But an inquest is not a criminal court, and so it was for another jury to decide whether Mr Duckenfield’s mistakes amounted to gross negligence manslaughter.
The crown’s case was that the Chief Superintendent’s failings were so extraordinary that they met that test.
But the jury accepted the defence case that the 75 year old was a target of blame who was unfairly singled out for prosecution.
He will now be able to resume his life in retirement on the south coast. But the Hillsborough families and survivors will find the outcome hard to take… and will ask hard questions about the £65m spent on a criminal investigation which has ended with no one convicted for so many lives lost.