A lawyer investigating the abduction and murder of University of Cambridge student Giulio Regeni has disappeared amid reports of his arrest by the Egyptian Security Services.

Ibrahim Metwaly, a central figure in the Egyptian Commission for Rights and Freedoms (ECRF), was due to fly to Geneva to address a UN working group about the Regeni case.

However, one of the ECRF’s lawyers claims to have seen Mr Metwaly at the office of the Egyptian state security prosecutor being interrogated on charges of “communicating with foreign entities to harm state security”. He was last heard from when he spoke to his family by phone at 8am on Sunday morning.

Mr Metwaly and the ECRF have represented the Regeni’s Italian family since their 28-year old son’s murder. Mr Regeni had been researching into the Egyptian union movement, a focal point for opposition to President Sisi, when he disappeared on January 25th 2016, the anniversary of the revolution.

When Mr Regeni’s corpse was discovered on February 3rd on the outskirts of Cairo, Egyptian authorities claimed that Mr Regeni had died in a traffic incident or a violent kidnapping.

However, it is widely believed in Italy that he was tortured and killed by Egyptian security services. Mr Regeni’s parents said that his body was so badly mutilated that they could only recognise him by his nose.

The incident resulted in diplomatic tension between Egypt and Italy, with the latter withdrawing their ambassador in April 2016 citing lack of co-operation on the part of Egyptian authorities. However, ties were restored last month, with the ambassador due to return on September 14.

In Cambridge, student campaigners and Labour MP Daniel Zeichner called for a stronger response to Regeni’s murder from the UK government. However, the University itself was denounced by Italy’s Deputy Minister for Foreign Affairs for an alleged lack of cooperation in the investigation, claims which the University has strongly denied.

According to Human Rights Watch, Sisi’s regime is responsible for the arrest of 60,000 opponents since it took power by military coup in 2013. Mr Metwaly’s own son disappeared four years ago and has not been heard from since.

Mohamed Lotfy, head of the ECRF, said the move had given the green light for Cairo to crack down on those involved in Mr Regeni’s case. “The message is clear: you can be a European citizen, be subjected to the most gruesome death and the state will still get away with it”, he said.