Christchurch police have released images of grass seeds found on the clothing of Mellory Manning, who was killed last month.
The 27-year-old had been working as a prostitute on the night of December 18.
Her body was found in the Avon River near Dallington Tce the following morning.
Police say that seeds found embedded in Ms Manning's cardigan and skirt clearly show she had been lying on grass before entering the river.
They say there's a good chance that whoever killed her also had seeds on their clothing.
The police still want to hear from people seen in Dallington Tce that night, and are keen for more information on a splashing sound heard by two witnesses.