London Zoo says it believes Melati carried the cub outside, but keepers are unclear as to how the cub got into the pool.
Keepers are now reviewing the situation because it was not forseen that the mother would take the cub outside so early.
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Minh Chi Lam, 58, subjected one of his victim, 18, to an hour long attack in the nail bar in east London.
The victim, in her 40s, was walking along Sutherland Road when she was suddenly was grabbed from behind.
The Terrence Higgins Trust claimed counselling services were threatened by reduced funding in Lambeth, Lewisham and Southwark.