Egyptian prosecutors on Wednesday ordered the detention for 15 days of a lawyer who assisted the family of an Italian graduate student who was killed under suspicious circumstances during a police crackdown in Cairo.
Ibrahim Metwally was accused by the Supreme State Security Prosecution of disseminating false news and "dealing with foreign parties".
The lawyer, who founded the Association for the Families of the Disappeared, was also suspected of having set up an "illegal" group, prosecution officials said.
Mr Metwally was arrested at Cairo International Airport three days ago while travelling to the Swiss city of Geneva to speak at a United Nations meeting on enforced disappearances.
[ Egypt rejected Italian request for phone records in Regeni investigation ]
[ Italy recalls ambassador from Egypt in protest over murdered student ]
He is now being held in Cairo's sprawling Tora Prison complex pending investigations.
The lawyer had provided legal services to the family of Giulio Regeni, an Italian researcher who disappeared on January 25 last year in Cairo and was later found tortured to death.
Egypt has faced accusations that one of its security services murdered the student but Cairo denied any such involvement. At the time of his death, Regeni was researching trade unions — a sensitive topic in Egypt.
The Italian's murder led to a diplomatic crisis that saw Italy recall its ambassador, although it has since said its envoy will take up his post again.
Rights groups accuse the Egyptian government of arbitrary arrests and enforced disappearances of dissidents which spiked after the military overthrew Islamist president Mohammed Morsi in 2013 and cracked down on his supporters.
The government disputes such allegations.
Metwally, who founded the Association for the Families of the Disappeared, was also suspected of having set up an "illegal" group, they said.