A park has been closed after safety fencing put up to guard against a 30ft-deep (9m) hole which opened up was stolen.
The hole, in Mountfield Park, Hellesdon, Norwich, was first thought to be a rabbit burrow.
The parish council had cordoned it off, but decided to shut the site after the fencing and warning signs were stolen.
"We could not guarantee the safety of people using the park," said Hellesdon parish clerk Mark Knight.
"The last thing we would want is a dog or, heaven forbid, a small child to fall into it and seriously injure themselves," he told the Local Democracy Reporting Service.
The park, off Mountfield Avenue, provides an open space, dog exercise field and pedestrian cut-through.
Mr Knight said contractors were investigating the problem and he hoped the park could be reopened "relatively soon".
"We think the hole could been a closed soakaway," he said.
"The groundskeeper originally thought it was a rabbit hole but after poking at it noticed it really was rather deep," he added.
The hole was originally discovered on 22 October, with the decision to close to park made the following day after the theft of the fencing.