CAIRO (Reuters) - Italian and Egyptian prosecutors discussed Egypt’s investigation into the killing of an Italian student on Tuesday and called the talks “positive”, after months of rising tension as Rome complained about a lack of cooperation from Cairo.

An Amnesty International activist holds a placard reading "truth for Giulio Regeni" as she takes part in a performance to protest against enforced disappearance in Rome, Italy July 13, 2016. REUTERS/Staff/File Photo

Giulio Regeni, who was doing postgraduate research into Egyptian trade unions, was last seen by his friends on Jan. 25. His body, showing signs of torture, was found in a roadside ditch on the outskirts of Cairo on Feb. 3.

Amid accusations from rights groups that Egyptian security services appeared responsible for the 28-year-old Regeni’s death, Italy complained that Egyptian authorities were not cooperating to find the perpetrators. In April, Rome withdrew its ambassador to Cairo for consultations.

Italian deputy chief prosecutor Sergio Colaiocco met Egyptian Public Prosecutor Nabil Sadek in Cairo on Tuesday and invited him to visit Rome in December for further talks and to meet Regeni’s parents, a statement by the two sides said.

“During the meeting amid a positive atmosphere, the two parties discussed the latest developments in the investigation and renewed their commitment to direct cooperation in uncovering the mystery of the incident and achieving justice for the victim,” the statement said.

In protest at the perceived sluggishness of the investigation, the Italian Senate voted in June to halt supplies to Egypt of spare parts for F16 warplanes.

Italy was Egypt’s fourth largest trade partner in terms of imports and exports in 2015, according to Egypt’s statistics agency CAPMAS. The Senate vote was Italy’s first commercial step against Cairo over the Regeni case.

Human rights groups have said that torture marks, including cigarette burns, cuts and contusions, indicated Regeni died at the hands of the security forces, an allegation Cairo denies.

But security and intelligence sources told Reuters in April that Regeni had been arrested outside a Cairo metro station on Jan. 25 and was taken to a Homeland Security compound.

Regeni’s case is an “open wound” for Italy, Foreign Minister Paolo Gentiloni said last week.

Sadek told his Italian counterpart in September that the head of Egypt’s independent union of street vendors reported Regeni to police a few weeks before he disappeared.

Police then carried out checks on Regeni’s activity for three days but found nothing of interest and stopped the checks, he said.

Regeni had been researching independent labor unions in Egypt for his doctorate studies at Cambridge University, and had been in contact with the leaders of the street vendors’ union.

Italy has significant economic interests in Egypt, including the giant offshore Zohr gas field, which is being developed by the Italian state energy producer Eni.

Prime Minister Matteo Renzi has also sought to be Egypt’s main political partner in Europe, offering to be “a bridge” to the region for Egyptian President Abdel Fattah al-Sisi.