NATO fighter jets were scrambled on Sunday evening after a private jet carrying four people veered off course and crashed off the coast of Latvia, authorities said.
What do we know so far?
German newspaper Bild reported that the plane, which was carrying the pilot, a man, a woman, and a child, had reported cabin pressure issues to air traffic control.
Bild said radio contact was lost as the plane left the Iberian peninsula.
The plane flew erratically at times, turning twice near Paris, France and at Cologne.
It then headed out over the Baltic Sea, passing near the Swedish island of Gotland, according to the FlightRadar24 website.
At 7:37 p.m. local time (1737 GMT) the jet was listed on the flight tracker as rapidly losing speed and altitude.
Agence France-Presse (AFP) reported that the plane crashed into the sea off Ventspills just before 8:00 p.m.
Latvia's civil aviation agency said its air traffic controllers had tried but were not able to make contact with the plane.
Fighter jets from Germany, Denmark and Sweden were scrambled to try to make visual contact with the crew "but they saw no one," Swedish search and rescue operation leader Lars Antonsson told AFP.
He said the plane flew relatively steadily until it neared the Latvian coast when it rapidly lost altitude and crashed "when it ran out of fuel."
Occupants 'clearly incapacitated'
Antonsson said "No human remains have been found" and although it's not known what caused the plane to fly off course "they were clearly incapacitated on board."
Aviation safety expert Hans Kjäll told Swedish news agency TT that cabin pressure problems could have caused passengers to lose consciousness.
This can happen quickly, especially at altitudes where small aircraft are used, he added.
The Swedish Coast Guard said they had discovered traces of oil on the water and smaller pieces of debris.
Helicopter, ships head to crash scene
A Lithuanian air force helicopter was dispatched to the crash site, a spokesperson for the country's military said.
Latvia's Navy said it had sent ships to the scene.
A Stena Line ferry traveling from Ventspils to Norvik in Sweden was also redirected to the crash site, according to the MarineTraffic website.
The website showed a Swedish search and rescue helicopter and airplane at the site as well.
The company listed as the owner in Austria's aircraft register, Cologne-registered GG Rent, could not immediately be reached for comment.
If confirmed, this would be the sixth time that a so-called ghost plane — where those on board were incapacitated — has crashed since 1980.
Four of the previous examples featured smaller planes, but the fifth involved a Helios Airlines commercial jetliner traveling from Larnaca, Cyprus to Prague in the Czech Republic.
The Boeing 737 crashed in August 2005 near Grammatiko, Greece, killing all 121 people on board.
mm/kb (AFP, Reuters)