Hossam Bahgat, one of Egypt's best-known advocates and founder of the Egyptian Initiative for Personal Rights in 2002, has been detained by the Egyptian military inside an undisclosed location as the investigative journalist faces charges for spreading "false news."

One of his lawyers, Adel Ramadan, said that the military prosecutors would not tell him where Hossam Bahgat is currently being held. All anyone has been told is that he was detained after being summoned to an intelligence building in Cairo.

"I asked the head of the military prosecution the place of detention, and was told I would not be told," Ramadan said. Bahgat will be held at least until Wednesday, according to Journal Sentinel.

Bahgat was honored with a Human Rights Watch Alison Des Forges Award in 2011. Bahgat's most recent report is about the August conviction of a group of military officers for plotting a coup.

"The arrest of Hossam Bahgat today is yet another nail in the coffin for freedom of expression in Egypt," said Philip Luther, director of the Middle East and North Africa Programme at Amnesty International in a statement. "The Egyptian military cannot continue to consider itself above the law and immune from criticism."

Egypt has been cracking down on various Islamists and other secular activists. On Sunday, Egypt's own state-run news agency had reported that the authorities had detained newspaper owner Salah Diab and his son on orders from the public funds prosecutor. Diab owns the independent daily Al-Massry Al-Youm, according to The Huffington Post.

If Bahgat is found guilty of the officials' claims, he could face up to five years in prison. The Committee to Protect Journalists, a New York-based press freedom organization, demanded for Bahgat be released immediately.

The International Center for Transitional Justice (ICTJ) also demanded that Bahgat be freed, claiming that his arrest is part of the Sisi government's "ongoing crackdown on journalists and demonstrators."

Since President Abdel Fatteh el-Sisi came to power in 2013, Egyptian authorities have been cracking down on journalists and press workers, according to Al Jazeera.