The police are looking for unknown perpetrators who are said to have unleashed a work ship on the Neckar.
The approximately 35-meter-long push barge was then driven along in the Schwabenheim Neckar Canal without a driver, according to a statement from the police on Wednesday.
Heidelberg - employees of the waterways and shipping administration finally succeeded in securing the push barge before major damage could occur.
The investigators are now betting that witnesses may have observed how perpetrators unleashed the secured ship on Saturday, it said.
dpa