Egypt deported a German citizen of Egyptian origin early on Friday who it detained in Cairo airport last month on suspicion of plotting terrorism, authorities said.Twenty-three-year-old Goettingen resident Mahmoud Abdel Aziz was repatriated on an early morning flight to Frankfurt in co-ordination with the German Embassy after being questioned by police, Cairo airport officials said. He had been detained on December 27.Security officials say interrogations revealed he believed in the extremist ideology of the Islamic State group.Another detained German, 18-year-old Isa El Sabbagh, from Giessen, is still in custody. He was stopped at Luxor airport on Dec. 17 and authorities also accuse him of supporting IS ideology that advocates terrorism.Christofer Burger, a Foreign Ministry spokesman, told reporters in Berlin that Egyptian authorities have confirmed El Sabbagh is in their custody, but that the German embassy had not yet been granted consular access to him."All we have received from the authorities is the confirmation that he is in custody," he said.Officials spoke on condition of anonymity as they weren't authorized to brief reporters. The German Embassy in Cairo could not be immediately reached for comment.German media have reported that both young men had been on trips intending to visit their grandparents. Egypt's Supreme State Security Prosecution is now leading an investigation into the men.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.