The reasons range from a flow of sewage water into the deer enclosure in February to mongoose bites which caused rabies - but all of these together have claimed the lives of 16 spotted deer at the National Zoological Park in New Delhi.

A part of the mystery also the fact that only the spotted deer were infected with rabies despite being located very close to the other deer enclosures. The Delhi Zoo has six kinds of deer, two of which are part of the conservation breeding programme under a participating zoo.

Zoo authorities cannot be reached for further comment as of now but the officials say that it will take nearly a month for the tests conducted on the animals to provide any conclusive leads to its origin.