harare u.s. citizen accuse attempt subvert president robert mugabe government release zimbabwe maximum security jail friday day high court order free bail reuters witness say judge clement phiri rule thursday patent absence facts state case 25-year-old martha donovan whose arrest last week center accusations insult 93-year-old mugabe twitter post deny accusation reuters witness saw donovan leave prison unite state embassy vehicle donovan lawyers speak reporters wait outside chikurubi maximum prison outskirts harare state prosecutors accuse donovan write twitter post october call mugabe selfish sick man government since last year target activists government critics use social media speak mugabe cash shortages bank foreign currency crunch cause sharp rise price amnesty international say fear donovan would last arrest government clamp social media platforms activist pastor evan mawarire whose thisflag movement last year organize big stay-at-home demonstration decade trial charge subversion face separate trial similar offence u.s. citizen face subversion charge zimbabwe release jail