“But we have received around 20 tips, of which several seem worth following up,” said inspector Anders Burén.
The body was found in the water near Ekerö, to the west of the capital, wrapped in a tarpaulin. A post-mortem examination has now been carried out. The woman was seven or eight months pregnant when she was murdered, police say.
The body was found by a jetskier on Sunday. Police say they are also talking to hospitals, particularly maternity units, to try to identify the woman.