The bodies of a 50-year-old man and an unidentified woman were found in two suitcases in Schlossgarten at 5.50pm after two people who had left a barbecue noticed a trail of blood and called the police.
The suitcases were hidden behind a concrete wall near Felix-Mendelssohn-Bartholdy-Allee, police said in a statement on Monday.
“The background and circumstances of the offence are completely open,” police said. A 40-strong team of officers has been set up to investigate the suspected murders.
An autopsy on the bodies is set to take place on Tuesday.