The suspect is described as white, about 20 years old, 6ft tall, thin, with dark wavy hair and thick bushy eyebrows.

BBC: E-fit of suspect

Tall and wiry, with a puff of wavy dark hair, he is nearly as well known in Washington for his punishing early-morning workouts as he is for his mastery of the federal budget.

NEWYORKER: Fussbudget