A wolf shot dead after escaping from Cotswold Wildlife Park may have climbed an electric fence.
Visitors to the park were told to stay indoors when the female animal, named Ember, was discovered outside the perimeter fence at 11:00 BST on Friday.
The park's managing director said staff were too far away to tranquilise the three-year-old Eurasian wolf.
An ongoing investigation by the park has found an electric fence was not properly charged.
Earlier this year Ember gave birth to five cubs, the first wolves to be born at the park in its 47-year history.
Managing director Reggie Heyworth said the park was still investigating how the wolf escaped, as there was no obvious breach in the fence.
He revealed the charge on the electric fence was not at the level it should have been and said it was possible she climbed over the barrier.
When keepers realised the animal was not in its enclosure the park's "emergency plan" was activated immediately.
'No other option'
Mr Heyworth added: "As a precaution, all visitors and other staff were notified immediately. Those that were indoors were asked to remain where they were.
"At no time were members of the public in any danger as the wolf was away from the visitor area throughout."
The wolf was found just outside the park's perimeter fence, towards the A361, and was shot by a member of staff.
Cotswold Wildlife Park said there was no other option as its staff were too far away to guarantee a tranquiliser dart would work safely.
Ember and two-year-old male wolf Ash arrived at Cotswold Wildlife Park from Sweden in October 2016 as part of a breeding programme.