Human Rights Watch, an international rights watchdog group, has criticised the United Arab Emirate's trial of Sheikh Issa bin Zayed al-Nahayan on charges of torture, saying it "needs to do more".
Al-Nahayan, the brother of UAE president and Abu Dhabi emir Sheikh Khalifa bin Zayed al-Nahayan, was acquitted of the charges against him in an Emirati court on Sunday, his lawyer said.
A video tape from 2004 showed Al-Nahayan torturing an Afghan man with whips, electric cattle prods and wooden planks with protruding nails.
The Emirati court, however, found that al-Nahayan was not responsible for his actions due to the influence of mood-altering medication.
Human Rights Watch (HRW) said in a statement coinciding with the trial that the UAE "needs to do more than quietly prosecute Sheikh Issa ... if it is to restore confidence in the country’s justice system".
"If the UAE government really wants to stop torture and to restore its sullied image, one trial will not be enough," Sarah Leah Whitson, HRW's Middle East director, said in the statement.
In the 2004 video tape, which was first broadcast by US's ABC news channel last April, a man in a UAE police uniform is shown tying up the victim's arms and legs, and later holding him down as the sheikh pours salt on the man's wounds. A Mercedes SUV later drives over the Afghan.
The rights watchdog called on the government to establish an independent body to investigate allegations of abuse by security personnel and other persons of authority.
It also urged the UAE to "ratify the UN Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment, and to renounce publicly and unequivocally the use of torture".