Prosecutors announced criminal charges on Wednesday arising out of the Hillsborough Stadium disaster, in which 96 supporters of Liverpool’s soccer team were fatally crushed and trampled in 1989 at a game in Sheffield, England.

There is no statute of limitations for serious crimes in Britain. Still, it is unusual for charges to be filed in such an old case.

But Hillsborough is unique. The death toll, which included 37 teenagers, and the number injured, more than 700, while severe, are not the only reasons the case has stayed active for so many decades.

Recent investigations have concluded that police negligence caused the tragedy. The police opened a gate that allowed a crowd of people to rush into the stadium, crushing those who were trapped inside. And when the chaos began, the officer in charge called for more security rather than ambulances.