So-called tarpaulin slashers stole solar generators worth around 80,000 euros on Wednesday night in a parking lot on Autobahn 14 near Könnern (Salzlandkreis).
The strangers had gained access to the cargo area of the truck and stole the equipment, the police said.
The 57-year-old driver of the truck was sleeping in his cab when the perpetrators struck.
Skills - then these disappeared in an unknown direction.
dpa