KEY POINTS:
A post mortem being carried out this morning on a body found in the Waimakariri River is expected to confirm that it is missing Christchurch girl Marie Davis.
The body was found by police divers in the river, on the city's northern outskirts, yesterday afternoon.
Fifteen-year-old Marie has not been seen since she was dropped off by a friend's mother at her suburban Papanui home about 6pm on Saturday, April 5.
Investigation head Detective Senior Sergeant Virginia Le Bas told Radio New Zealand today the body was found submerged under water.
She said the body could have moved down the river from where it was originally, because of river flow.
Police had called in experts in river flow who should be able to give some idea where the body first entered the river.
The search of the river bed and surrounding banks was prompted by a number of disturbances in the area, including a scream, on the night Marie disappeared and a tip-off from a member of the public.
After 12 days of "anger and hope and now grief", Marie's family were fearing the loss of the "most awesome person".
Marie's elder sister, Amy, said she would miss her sister, who was "one of the nicest, greatest and most awesome persons around".
"I love her very much and I'm going to miss her and wish that she was still around," she told The Press.
"I hope this person or people will be caught. If anyone has any information, please come forward."
Outside Marie's home, cousin and family spokesman Nick Donald said: "We are just supporting each other and helping each other through."
"You go through different stages throughout the whole process of wondering why, and anger and hope, and now I think it's grief."
Mr Donald said that throughout the search "you've got in the back of your mind, 'I hope she's still alive', but after what they found today, it's not looking very good at all".
He appealed for anyone who knew about Marie's death to come forward.
Mr Donald said the family still did not know whether Marie had left home of her own accord or was taken.
Denis Pyatt, principal of Papanui High School where Marie was a student, said special assemblies would be held today in recognition of her.
Ms Le Bas said police would continue searching the river and surrounding areas upstream of the motorway bridge today.
She said belongings of Marie were also found but she would not say what those items were.
- NZPA