Lawyer says prosecutors have ordered Hazem Ghonim to remain in custody for 15 days pending an investigation.

Egyptian prosecutors have ordered the brother of a United States-based activist to remain in detention amid an ongoing investigation into allegations against him that include joining an outlawed group and spreading false news, according to a lawyer.

Mohammed el-Baker told The Associated Press news agency on Sunday that the prosecutors had ordered Hazem Ghonim to remain in custody for 15 days.

Hazem is the brother of Wael Ghonim, who led a Facebook page that helped ignite the 2011 Egyptian uprising that toppled former President Hosni Mubarak.

In a series of posts published on his Twitter account, Wael Ghonim said security forces raided his family’s home in Cairo and took the passports and cellphones of his relatives before arresting his brother on Thursday and taking him to an unknown location.

Wael Ghonim accused President Abdel-Fattah el-Sisi‘s son Mahmoud el-Sisi, who was appointed deputy head of the general intelligence directorate last year, of leading what he described as the “kidnapping” of his brother.

He claimed that his recent criticism of el-Sisi prompted authorities to retaliate by detaining his brother, especially after he rejected the Egyptian embassy in Washington’s “indirect threat” to “go silent or work with them”.

The Egyptian State Security arrested my brother: Hazem Ghonim after I rejected their request to go silent or work with them. Shame on you Sisi. You will pay a huge price. — Wael Ghonim 🦅 (@Ghonim) September 19, 2019

Wael Ghonim called on the Egyptian authorities and US President Donald Trump to release his brother from detention.

Describing his brother as “apolitical” and reiterating that he would not “be silenced” by the el-Sisi government, Wael Ghonim said he would launch an international media campaign to shed light on his brother’s case if he was not released in the coming days.

Followed by 2.9 million Twitter users, Wael Ghonim also urged his followers to share his brother’s story using the hashtag #SaveHazem in hopes of gaining the international community’s support.

Hey tweeps, can we show my brother #saveHazem some virtual love and retweets? The dictatorshit that is run by @AlsisiOfficial kidnapped Hazem to silence me from speaking up. My family, especially my terrified mom will be grateful forever. Hazem must be freed NOW! pic.twitter.com/mHahjEZDEa — Wael Ghonim 🦅 (@Ghonim) September 21, 2019

The arrest came as Egyptian social media was awash with calls for anti-government protests last week, led by a self-exiled Egyptian businessman, Mohamed Ali, who has accused el-Sisi and his aides of squandering public funds on vanity projects.

El-Sisi denied all corruption allegations last week.

On Friday, thousands joined in rare protests in Cairo and other cities. Since coming to power in 2014, el-Sisi has overseen a broad crackdown on dissent including the jailing of thousands of dissidents and the effective banning of protests.

El-Sisi led the military removal of former President Mohamed Morsi in 2013 and won back-to-back landslide elections after running virtually unopposed.

About one in three Egyptians live below the poverty line on less than $1.40 a day, according to official figures released in July. Other estimates put the figure higher.

On Saturday, Ali urged Egyptians to join a “million-man march” next Friday and to fill all “major squares” of the country.

“This is a people’s revolution … We have to link up together as one … and organise going down to the major squares,” he said in a Facebook appeal to his followers.