The Star newspaper was told a garden gnome was used in the attack and police believed it may have been dumped in the Waimakariri River.
Police have refused to discuss specifics of the case have confirmed they searched the area for "items of interest".
Ms Lawrence's family issued a statement this evening, saying she was a much-loved and integral member of the family.
" ... a wonderful mother, nana, daughter, granddaughter, sister and aunty who loved life and lived it to the fullest. She will be dearly missed by all who loved and knew her.
"At this time we ask the media to please respect this is a very hard time for us and thank them in advance for respecting our privacy."