LONDON (AP) — Britain’s Court of Appeal has exonerated three Black men who were convicted of robbery nearly 50 years ago, the latest in a series of cases that have been overturned because they relied on the testimony of a corrupt police officer who later died in prison. The court on Monday quashed the convictions of Courtney Harriot, Paul Green and Cleveland Davidson, who were aged between 17 and 20 when they were accused of trying to rob a plainclothes detective on a London Underground train. The men always maintained their innocence and claimed that they were framed by the officer before his career ended in disgrace.