Police are investigating after an underwater environmental monitoring station that was moored on the sea bed in Germany has vanished.
A German research organisation has been searching for the station since it disappeared a month ago.
The device, which measured water flow and methane concentration among other things, was located 22 metres under the surface of Eckernfoerde Bay in northern Germany.
It weighed some 740 kilograms and was moored by thick cables.
The Geomar ocean research centre says data transmission ended abruptly on August 21.
Researchers first suspected a transmission failure, but divers sent down last week discovered that the equipment was missing and saw only a frayed cable.
News agency DPA reported on Thursday that Geomar said divers took a second look this week and found only parts of the station's supports. Police have now launched an investigation.