The New York-based Human Rights Watch says the families’ letter Sunday claims the suspects have suffered abuses such as long periods of solitary confinement and lack of proper medical care.

The activists face accusations of threatening the UAE’s stability and “insulting” rulers by joining Internet campaigns calling for a greater public voice in political affairs.

The activists include a prominent blogger and a trade law expert who has lectured in the Abu Dhabi branch of Paris’ Sorbonne university.

They could face decades in prison if convicted.