Egyptian police arrested an Alexandria University ex-professor who testified for the Human Rights Watch, or HRW, report on the Rabaa massacre, the local online newspaper Mada Masr reported. One source said the police arrested Mohamed Tarek during an anti-regime protest in Alexandria, close to Moharram Beik Bridge. Tarek was detained by security forces, the Arabic-language newspaper Al-Masry al-Youm said.

Tarek was arrested on accusations of running pages on social media, inciting violence against police and military forces, according to the newspapers. Sources close to the investigation said he will mostly likely be charged with providing false testimony in the HRW report.

Sarah Whitson, director of the HRW Middle East and North Africa division, said on Twitter that the arrest was “bogus”:

Tarek’s arrest comes after HRW released a report that detailed the shooting of at least 800 protesters in one day. Following the ouster of President Mohammad Morsi, tens of thousands of Egyptians set up camps to protest the removal of the democratically elected president. Security forces stormed one of the country’s biggest protest camps in Rabaa. The HRW report said the Rabaa killings constituted a crime against humanity under international law. The organization found the event was “one of the world’s largest killings of demonstrators in a single day in recent history.”

The Egyptian government accused HRW of breaking the law, violating Egypt’s sovereignty and insulting the judiciary. In a statement following the report, the Egyptian government said HRW “does not enjoy any legal status that may allow it to operate in Egypt” and that “[c]onducting investigations, collecting evidence and interviewing witnesses without any legal backing are activities that constitute a flagrant violation of state sovereignty under international law.” These allegations can lead to jail time in Egypt for the organization’s staff members and, now, for those who participated in testifying for the report.