A sophisticated underwater observatory has disappeared from the Baltic seabed, baffling scientists.

The observatory, which was in a restricted area at the entrance to Eckernförde Bay off the German coast, made its last data transmission on Aug. 21.

Installed by German research organizations GEOMAR and HZG in December 2016, the observatory comprised two racks containing monitoring equipment, with a combined weight of 1,631 pounds. The equipment was connected to the German mainland via a huge cable, according to researchers.

“At first we thought of a transmission error,” said professor Hermann Bange of GEOMAR, in a statement translated from German. “When the divers reached the bottom of the sea last week at the observatory’s location, they found only the torn off land cable. It was completely shredded.”

Experts have not had any success locating the missing devices and have appealed for information from people in the nearby coastal area. “Maybe someone saw something on the morning of August 21,” said Bange. “Or someone finds parts of the frames somewhere on the beach.”

Local police have also been notified about the missing observatory.

The monitoring station cost about 300,000 euros ($332,000) and provides “priceless” scientific data about changes in the Baltic Sea, according to Bange. “Therefore, we will try to get the observatory back up and running as soon as possible,” he said.