The Star has been told that the gnome used in the attack was believed to have been dumped in the Waimakariri River.
Police yesterday refused to discuss specifics of the case or confirm they were looking for a gnome in the river.
But Detective Senior Sergeant Corrie Parnell said police searched the river on Monday for "items of interest" in connection with the assault. However, nothing was recovered.
Ms Lawrence remains in Christchurch Hospital in a critical condition.
Police were alerted shortly after the attack by ambulance, and later on Sunday night located Foley.
A large police cordon surrounded the block of five flats yesterday as a forensic examination continued.
An unmarked police car and police caravan was parked out front, while a large tent was erected in the middle of the driveway, beside halogen lights and a generator.
Garden ornaments were spotted at the front sliding door yesterday but police officers refused The Star photographer permission to take pictures.
Detective Senior Sergeant Parnell said he expected the scene examination to be complete today. He said police had also located a green Toyota Camry sedan wanted in connection with the incident which was yet to be examined.
Neighbours were shocked by the alleged violent incident, which has attracted a major police presence since the early hours of Sunday morning.
One resident, who did not wish to be named, said the Worcester St flat, near Linwood Ave, has been a troublespot for the street.
"I arrived here at my brother's house on Thursday night and my brother, who's lived here for years, was saying how p***** off he was with the noise coming from that house.