A teenager was still being questioned after a six-year-old boy was thrown five floors from the 10th floor of the Tate Modern art gallery in London.
The boy, who landed on the fifth floor roof, is in a stable but critical condition following the fall on Sunday.
A witness said they heard a "loud bang", before seeing a woman scream: "Where's my son, where's my son?"
A 17-year-old boy arrested on suspicion of attempted murder remains in police custody.
The Met Police said the six-year-old was thrown from a viewing platform.
BBC
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Donald Trump has confirmed that he will not take part in Republican presidential debates with his rivals in the race for the White House.