Win Htein, a senior aide to Myanmar’s ousted leader Aung San Suu Kyi, was sentenced to 20 years in prison on Friday on charges of high treason, media and one of his family members said.

Win Htein, 79, is a stalwart supporter of Suu Kyi and a long time political prisoner during decades campaigning to end army rule. He was arrested after the February 1 coup that plunged Myanmar into chaos and that ended a decade of democratic rule.

Win Htein’s daughter, Chit Suu Win Htein, said in a message to Reuters: “So this is as we expected. It’s not a surprise but it’s a sad and outrageous thing to hear about the ridiculous sentencing. Perpetrators of this injustice will be held accountable for this.”