Qld police defend search for dead girl

Police have defended the time it took to alert the public about a missing Queensland schoolgirl whose body was found on a riverbank almost a week after she disappeared.

Police say Tiahleigh Palmer, 12, was last seen being dropped off by her carer at Marsden State High School in Logan about 8.10am on Friday, October 30.

Her body was found on the banks of the Pimpama River on the northern Gold Coast on Thursday afternoon.

Her grandmother Sue Palmer is struggling to come to terms with Tiahleigh's death.

"She is, she was, a very beautiful girl," Ms Palmer told the Nine Network.

"I want to pick up that little girl and cuddle her and tell her I'm so sorry that we've let her down."

Tiahleigh's school friend, Ciara Ladd, said the keen dancer was very funny and always smiling.

"She'd always make everyone happy," Ciara told the Nine Network.

Police had only issued an alert about Tiahleigh's disappearance early on Thursday - six days after she was reported missing.

But Detective Superintendent Dave Hutchinson said police had been busy interviewing witnesses and reviewing CCTV footage behind the scenes.

"Throughout that whole period there was a whole range of investigations being conducted and there were a number of (unconfirmed) sightings," Supt Hutchinson said.

He said he was concerned with finding out what happened to Tiahleigh, rather than questioning the merits of the investigation.

"What we're here talking about today is the investigation of the location of a deceased child, OK?" Supt Hutchinson told a news conference on Saturday.

"We're interested in what's happening from now on ... anything that might have occurred prior to this, those further investigations, I can talk to you (about) later."

Supt Hutchinson said the homicide squad was investigating because no cause of death has been determined.

An autopsy was carried out on Friday, but decomposition and damage caused by Tiahleigh's body being in water hindered investigations.

Supt Hutchinson has called on anyone who has come across a white Marsden State High School uniform or distinctive pink Mambo backpack to come forward.

Those items, which Tiahleigh was wearing when she was dropped off at school, have not been found.

Supt Hutchinson also called for people driving past the school on the morning of October 30 who have cameras attached to their vehicles, or those who were in the area of Pimpama River on Thursday afternoon, to contact police.