CAIRO (Reuters) - Egyptian and Italian prosecutors have found gaps in footage from inside and around Cairo metro stations where murdered Italian student Giulio Regeni disappeared in 2016 and will seek to discover the cause, they said on Wednesday.

FILE PHOTO - A man holds a placard during a vigil to commemorate Giulio Regeni, who was found murdered in Cairo a year ago, in downtown Rome, Italy January 25, 2017. REUTERS/Alessandro Bianchi

They said the recordings which were examined by experts representing both prosecution offices showed no “videos or images” of Regeni, a 28-year-old PhD student who was researching the Egyptian labor movement, disappeared in 2016 and was found murdered almost a week later.

“Through examinations, a number of ‘gaps’ appeared in the recovered content - images and videos that are lost and haven’t been restored - and as such, the view of the two prosecutors concluded that there is a need to conduct further advanced technical checks to find out the reasons for that,” said the statement, issued by the Egyptian prosecutor’s office and sent to journalists.

“This is what the Egyptian public prosecutor has ordered ...,” it added, referring to the checks.

The statement said that as part of the joint cooperation between the two prosecution offices in trying to find out those behind the kidnapping, torture and killing of Regeni, the next meeting to review the investigation would be held after the checks are conducted.

A similar statement was issued in Rome by the Italian capital’s prosecutor and carried by Italy’s ANSA news agency.

Egypt agreed last year to allow experts from Italy and a German company that specializes in salvaging CCTV footage to examine cameras in Cairo.

Regeni disappeared on Jan. 25, 2016 the anniversary of the start of 2011 uprising that ended Hosni Mubarak’s 30-year rule. His body was discovered on Feb. 3 and Egyptian investigators found signs of extensive torture.

Intelligence and security sources told Reuters in 2016 that police had arrested Regeni outside a Cairo metro station on Jan. 25 of that year and then transferred him to a compound run by Homeland Security.

Egyptian officials have repeatedly denied any involvement in Regeni’s death.

The case had strained ties between Egypt and Italy, which recalled its ambassador over the case. Relations were restored in August last year when Rome said it would return its envoy to Cairo and continue to search for Regeni’s killers.