Authorities are hunting an American hitwoman, who disguised herself in a hijab as part of a bungled murder plot in Birmingham. Aimee Betro, 44, was hired to travel from the States to the West Midlands to kill boutique clothing store owner Sikander Ali. But the plot, orchestrated by two business rivals, failed when the would-be assassin’s gun jammed. Police have launched an international hunt to find Betro, after the two men who hired her were convicted of conspiracy to murder. Birmingham Crown Court heard how Mohammed Aslam, 56, and his son Mohammed Nazir, 30, had held a grudge against Ali and…