A Syrian migrant deemed to pose a threat who was investigated for terror was able to board a flight from Germany to Greece, despite being electronically tagged.

The 35-year-old, known as Hussein Z., is likely to have come to Germany in February 2015 as an asylum seeker and is thought to have been living in the town of Aschaffenburg in northwest Bavaria.

He had been investigated on suspicion of membership of a terrorist group, according to Die Welt, and the Bavarian state protectors classified him as “particularly dangerous”, likely because of Islamist views.

His movements were supposedly being tracked and controlled, yet he was able to walk on to a commercial fight unopposed.

The Federal Police told Bavarian Radio: “In principle, an electronic ankle tag does not pose a risk to air traffic. On the other hand, under European Union law, the person was not allowed to go through border control and an internal border was crossed.”

Syrian Teen Arrested For Plotting Terror Attack Was Given Asylum Without Vetting, Background Check

https://t.co/dNkXhiIGoP — Breitbart London (@BreitbartLondon) November 6, 2017

The man reportedly said he wanted to pick up his son from the Turkish-Syrian border area. His mother and sister are already lived in Hamburg, according to security sources.

Authorities were unable to track the man for the three hours he was in the air and were forced to turn off the tracking device when he was detected in Athens, Greece, for legal reasons.

German authorities were quick to contact their counterparts in Greece and warn them, but it was too late, and the man’s whereabouts are now unknown. An arrest warrant has been issued across the Schengen area.

In February last year, German authorities admitted they did not know the whereabouts of 130,000 migrants.

Of the 1.1 million migrants who registered as asylum seekers in Germany in 2015, “about 13 per cent did not turn up at the reception centers to which they had been directed,” the government said in a written reply to a question.

However, reports from earlier this year suggest there could be as many as 1.6 million asylum seekers in the country, plus another 392,000 whose status was unknown, and an estimated 30,000 missing.