Wels prosecutor Alois Hubmer said that the witness told him that a pair of hands and feet were clearly visible.
Police sniffer dogs found a second suitcase on Monday morning on the shore of the lake, containing further body parts.
Later on Monday police divers discovered the body of a man in the lake. They are currently investigating whether he killed and dismembered the woman, and then drowned himself.
The first suitcase was found near Gmunden, not far from the Ramsauerwirt restaurant, which is closed for the winter.
After carrying out an autopsy late on Sunday night the Salzburg coroner said that the remains in the suitcases belonged to a woman who was between 50 and 70 years old.
Police said she may have been murdered quite recently. So far they have declined to release any further details as to the state of her body or how she died, in case it endangers their investigation.
They did say that the body is not believed to be that of anyone currently on the missing person's register. Identification is made more difficult as the woman's head is missing.