A common figure in activism in Egypt and who was released on probation in March was arrested on Sunday according to his family and a security source.

His arrest comes amidst what activists say is the largest wave of arrests since President Abdel Fattah al-Sisi took office.

Rights groups in that country say at least 1,900 people have been detained since anti-government protests began in Cairo and other Egyptian cities last week.

The public prosecutor’s office said on Thursday no more than 1,000 suspects had been questioned.

Alaa Abdel Fattah, a blogger and software engineer, was released in March after serving a five-year sentence for protesting without permission in breach of a 2013 law that rights groups say effectively bans protests.

Under the terms of his release, Abdel Fattah was required to spend his nights at a police station for five years. His family said he was rearrested on Sunday morning as he was preparing to leave the station.

“I arrived at the police station and I found the place where he spends the probation empty, I asked them where Alaa was,the chief detective came out and told me that Alaa is at the national security prosecution.” his sister Mona said.

The Interior Ministry could not immediately be reached for comment, but a security source said an arrest warrant had been issued against Abdel Fattah over accusations of publishing false news and inciting people to protest.

Abdel Fattah was a leading voice among the liberal youth who initially led the 2011 uprising that ended the 30-year rule of autocrat Hosni Mubarak.