Chania (Greece) - Call for help from the Greek vacation island of Crete ! The German tourist Johann W. (20) has been missing there since Thursday evening.

"The police, fire department and mountain rescue are already searching for him. Today is the fifth day he has been missing, so it is very important to find him as soon as possible," wrote Sister Teresa on social media on Monday.

W. apparently wanted to cross the famous Samaria Gorge (17 kilometers long) in the regional district of Chania alone, but was not seen afterwards. He also did not return his rental car and did not answer his cell phone.

"At 7.40 pm, he told me that everything was fine. He may have been on the summit of the Gingalos mountain at the time. So maybe something happened to him on the way back to the parking lot," Teresa suspects.

Her urgent appeal: "Any additional help in the search is a great help, as the area where he could be is quite large." To this end, she linked the GPS data to her brother's last whereabouts.

It remains unclear why the missing man set off for the gorge. The route is not actually passable in winter. W. comes from Baden-Württemberg and studies computer science in Mannheim.