A US national held in Saudi Arabia has received a 16-year jail sentence for writing tweets critical of the government, his son has told the BBC.
Saad Ibrahim Almadi, 72, who also has Saudi citizenship, was arrested in November after he travelled from Florida to Riyadh to see his family.
His son has now spoken out for the first time publicly, going against what he says has been US official advice.
Ibrahim Almadi said he did not want to see his father die in prison.
He alleged that Saad had been held in conditions that amounted to torture since his arrest by Saudi authorities.
The Saudi court that issued the prison sentence found him guilty of trying to destabilise the kingdom and of supporting and funding terrorism.
Ibrahim says the only evidence finally presented to the court consisted of 14 tweets.
The tweets, which the BBC has seen, include criticism of the demolition of old parts of the cities of Mecca and Jeddah, concern over poverty in the kingdom, and a reference to the murdered Saudi journalist Jamal Khashoggi.
Saad was also found guilty of not reporting terrorism over tweets that Ibrahim had posted on a separate account, according to his son.
Prosecutors wanted to sentence him to the maximum of 42 years in jail, he said. Two weeks ago, he was sentenced to 16 years in prison and a subsequent 16-year travel ban, he added.
Although Ibrahim has not been able to speak to his father since he was arrested, family members in Saudi Arabia have said they have been given access to Saad and that he told them that he was fine.
Ibrahim expressed his scepticism over this to the BBC.
