Bulgaria is looking for mysterious pilots who have flown across several European countries

The Bulgarian authorities are looking for a mysterious pilot who flew unauthorized through several European countries.

The country’s defense forces were put on high alert Wednesday evening when a small plane was detected in its airspace.

According to Interior Minister Boiko Rashkov, the Beechcraft tandem plane departed from Hungary and flew over Poland and Slovakia.

The pilot is therefore believed to have landed near the Black Sea, after briefly passing through Serbia and Romania.

The 60-year-old plane was finally found with the engine still warm on the runway of a private airport in the north-east of Buhovtsi. It was covered by a tarp and there was no sign of the crew.

The suspect plane did not have a flight plan, had deactivated its transponders and did not respond to radio messages or visual signals, the Bulgarian Ministry of Defense said in a statement.

The Beechcraft aircraft was also followed and escorted by Hungarian and Romanian fighters.

Bulgarian Defense Minister Dragomir Zakov told reporters that the plane “never posed a threat”.

“It was flying at a very low altitude and low speed, which makes it difficult for fighters to intercept,” he added.

The prosecutor in Varna, eastern Bulgaria, has opened an investigation into the incident.