Again and again for much of his life, Omar Mateen let people know he was a violent, dangerous person capable of murder. Repeatedly, he wiggled out of trouble, distracting officials with a beguiling charm, a feigned stupidity or some other tactic.

A look at Mateen’s troubled life, based on interviews with officials and people who knew him, as well as documents, reveals that on at least a dozen occasions, beginning when he was in grade school, he gave clues in a public setting that he was capable of mayhem.

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