The trial of former Egyptian President Mohamed Morsi, deposed by the army and sentenced to 20 years in jail, was "badly flawed" and appears to have been politically motivated, Human Rights Watch said on Sunday.
A court on April 21 convicted Morsi and 12 other Muslim Brotherhood members of violence, kidnapping and torture over the deaths of protesters in 2012. They were acquitted of murder, which carries the death sentence.
The rise to power of the Brotherhood, a decades-old Islamist movement, after the Arab Spring uprisings polarized Egypt's population and led to months of unrest.
The army ousted Morsi in mid-2013 after mass protests against his rule. Abdel-Fattah el-Sissi, army chief at the time, went on to win presidential elections last year.
Human Rights Watch said Morsi's detention without charge for more than three weeks after his removal from office violated Egyptian law, and it criticized the prosecution's heavy reliance on the testimony of military and police officers.
"Whatever political responsibility [Morsi] may have, the prosecution didn't establish his criminal guilt in this case", the rights group said in a statement entitled: "Egypt: (Morsi)Trial Badly Flawed"
It also cited a spokesman for the defense team saying the lawyers were only allowed to visit Morsi once in November 2013.
Another lawyer was cited as saying the defense did not call witnesses out of fear for their safety.
Reuters could not immediately reach a foreign ministry spokesman for comment on the report, but a government statement last week rejected criticism of the Morsi's sentencing as "unacceptable interference in [Egypt's] internal affairs, let alone disrespect of the rulings of the Egyptian judiciary."
Morsi and his co-defendants deny the charges against them and are expected to appeal. Their case is part of a wider crackdown on the Brotherhood launched after the army overthrew the Islamist president.
Harsh rulings against thousands of Morsi supporters, including death sentences handed down in mass trials, have been widely condemned abroad, including by rights groups, the United States and the European Union.
HRW also said the authorities had not investigated the killings of Morsi supporters at the 2012 demonstrations, creating "an appearance that the case was politically motivated against the Brotherhood".
Morsi faces charges in four other cases including leaking secrets to Qatar, conspiring with the Palestinian militant group Hamas to destabilize Egypt, and organizing a jailbreak during the 2011 uprising against Hosni Mubarak.