HARARE - Zimbabwe freed on Thursday a 25-year-old American journalist charged with subverting President Robert Mugabe on account of an alleged tweet that described the ageing leader as “selfish and sick”.

Martha O’Donovan had been charged with attempting to overthrow Mugabe as well as undermining or insulting the veteran leader, now 93.

The arrest of O’Donovan and the seizure of her laptop in a dawn raid at her apartment last Friday came just weeks after the government appointed a cybersecurity minister tasked with policing social media.

“Ms Martha O’Donovan has been granted $1,000 bail (860 euros) and ordered to reside at a given address, surrender her passport... and report twice a week” to detectives, said O‘Donovan’s lawyer Obey Shava, speaking outside Harare’s High Court.

Prosecutors say that on October 11, O’Donovan tweeted on her @matigary account: “We are being led by a selfish and sick man.”

The tweet was illustrated with a photo showing the Zimbabwean president with a catheter device.

The judge sided with the defence and accepted that the state had failed to justify the reason for remanding her in custody.

O’Donovan works for Harare-based Magamba TV, which describes itself as a leading producer of cutting-edge political satire and comedy. Its content is uploaded to YouTube.

Human rights lawyers had said previously that the arrest was linked to a retweet which did not mention Mugabe by name but referred to a “goblin whose wife and step-son bought a Rolls-Royce”.

Mugabe’s stepson with his wife and first-lady Grace is thought to have recently imported two of the British luxury cars, according to local media reports.

The cybersecurity ministry was created in Mugabe’s latest cabinet shuffle last month and is seen by rights groups as an attempt to clamp down on social media ahead of next year’s election.

Mugabe has already been named by his ruling ZANU-PF party as its presidential candidate for the 2018 vote.