Former Nicaraguan rebel leader Hugo Torres has died in prison aged 73, eight months after being detained on treason charges.
The retired army general fought alongside current President Daniel Ortega during the country’s revolution, helping free him from jail in 1974.
But he later accused Mr Ortega of becoming a dictator and founded an opposition party.
Torres had been transferred to a hospital after his health deteriorated and died there of an undisclosed illness, the government said.
Torres’ children expressed their “deep pain over the death of our beloved father”.
Torres was seen as one of the heroes of the Sandinista Revolution against the brutal dictatorship of Anastasio Somoza in the 1970s.
He took part in a risky operation to free Mr Ortega, who was being held by Somoza’s regime.
But Torres was among 46 former rebels arrested in June in what critics called a crackdown on opponents of Mr Ortega. They were prevented from contesting elections which saw Mr Ortega elected for a fourth consecutive term.
Torres – then vice-president of Unamos, an opposition party created after the spit from Mr Ortega in 1995 – was charged with “conspiracy to undermine national integrity”.
Unamos said Torres had been subjected to “physical and psychological torture” since he was detained. The party said it asked the government about his declining health last month, but it did not respond.
Torres had been “denied freedom in inhumane conditions and subjected to a legal process with no guarantees”, the UN High Commissioner for Human Rights Michelle Bachelet said.