Mr Agus said each of the zoo’s lions - there are now only four left - spends its days in two different cages.
Each morning, the lions are taken to a display cage where visitors can view them. Then, in the afternoon they are moved to another cage where they sleep, said Mr Agus.
He explained that the zoo used steel cables to secure the cage so zookeepers did not have to manually open or close the cage door with their hands.
This, he said, was a safety precaution to prevent the keepers being injured.
Michael was sent to the zoo last March by the East Java Natural Resources Conservation Agency.
Surabaya Police detectives chief Senior Commander Farman told the Globe that a team of officers had visited the zoo to gather evidence but the corpse was missing.
He said that if the lion’s body could be found ‘we are going to wait for the autopsy results, then we can further examine the case.’
A MailOnline investigation into the zoo before Christmas found numerous cases of animals living in miserable conditions, including a young elephant that was chained by three legs, one of which was ulcerated because of its tight shackles.
Dozens of petitions were started pleading for the zoo to be closed and animal rights groups have added their voice to the demands.
But a management team, headed by the Surabaya Mayor, Mrs Tri Rismaharini, has resisted improvements saying they want to retain the original structures erected by Dutch colonialists in 1916.