CAIRO — Egyptian authorities freed an Egyptian-American on Saturday who was sentenced to life in prison and had been on hunger strike for over a year, forcing him to renounce his Egyptian citizenship as a precondition of his release.

Mohammed Soltan, the son of a prominent member of the now-outlawed Muslim Brotherhood, had been convicted on charges of financing an anti-government sit-in and spreading “false news,” one of thousands imprisoned after the 2013 military overthrow of Islamist President Mohammed Morsi.

Soltan’s release comes amid international criticism over Egypt’s mass trials and imprisonments, and only days before President Abdel-Fattah el-Sissi travels to Germany on a state visit.

Soltan, a 27-year-old Ohio State University graduate and former Barack Obama campaigner, was arrested in August 2013 when security forces came looking for his father at his home.

His family said they didn’t find the father at the time, but arrested him instead. His father, Salah, was detained later.

Soltan had had been on a hunger strike over his detention for over 16 months and his family said his health had been rapidly deteriorating.

Egyptian officials, who spoke on condition of anonymity because they weren’t authorized to brief journalists, said Soltan boarded a flight for Frankfurt, Germany, early Saturday en route to the United States, using a U.S. passport.

Waleed Nasser, one of the lawyers representing Soltan, said that he was forced to renounce his Egyptian citizenship in order to secure his release. A decree el-Sissi issued in November allows him to deport foreign defendants convicted or accused of crimes.

Nasser said Soltan required a wheelchair and was travelling with a nurse and U.S. State Department official, with plans to arrive in Washington on Saturday night.

In a statement, Soltan’s family thanked those who helped work for his release, saying that the U.S. government had made extensive efforts to secure his return home.

“Mohammed’s health is dire,” his family said. “He will receive medical treatment as soon as he arrives on U.S. soil and will spend the immediate future with his family recovering.”

A State Department statement released Saturday welcomed Soltan’s release.

“We believe this step brings a conclusion to this case and we are glad Mr. Soltan will now be reunited with his family in the United States,” it said.

A criminal court in April sentenced Soltan to life, while upholding death sentences for 14 people, including his father and Brotherhood leader Mohammed Badie, and sentencing 36 others to life in prison, including three Egyptian journalists.

The case is rooted in the violence that swept Egypt after the military-led ouster in July 2013 of Morsi, a veteran Brotherhood leader and the country’s first freely elected president.

His supporters set up protest camps in Cairo, but security forces violently dispersed the sit-ins in August 2013, killing hundreds. In retaliation, many police stations and churches came under attack.

Soltan had been working as an assistant and translator for U.S. and international news organizations during the protests, but prosecutors accused him of participating in a plan to overthrow the country’s military rulers.

His lawyers said they believe Soltan’s hunger strike was the longest ever in Egyptian prison history, adding that he started it to protest “deplorable conditions of his incarceration and his abuse in custody.”

They described the proceedings against him as “a Kafkaesque political show trial.”

“No credible evidence was ever presented to warrant his detention, nor did Mohammed’s trial approach internationally recognized minimum standards of due process,” they said in a statement.

Many others remain in Egyptian prisons in similar cases, such as photographer Mahmoud Abou-Zeid, known by his nickname Shawkan, who was also arrested in August 2013 while taking photographs of the violent dispersal of a sit-in.

El-Sissi, who as army chief led Morsi’s overthrow amid mass protests against the Islamist leader, travels to Germany next week to meet Chancellor Angela Merkel.

Germany’s Parliamentary Speaker Norbert Lammert last week called off a meeting planned with el-Sissi due to human rights violations in Egypt.

“What we are witnessing in recent months is systematic persecution of opposition groups, with mass arrests, convictions to lengthy prison terms and an incredible number of death sentences,” Lammert said in a statement.