The US suburban couple accused of a bungled treason plot

They seemed to be living the most ordinary of lives, Jonathan and Diana Toebbe – professional, comfortable, unostentatious.

Their red-brick house in a posh part of Annapolis, Maryland – a coastal city of Romanesque churches and beaux arts-facades – held the comfortable clutter that comes with two children and two pitbulls, Sasha and Franklin, whose names are emblazoned on the front step welcome mat.

The neighbourhood streets are lined with cypress trees. Oyster shells are strewn in the grasses of a park close by, Quiet Waters. Yards are neatly mown, and the grass smells sweet. The US Naval Academy is nearby, as is a yacht harbour.