In the meantime, officers today returned to the streets around Oceanview Heights school in Timaru to speak again with neighbours.
They are especially keen to interview Catherine Sadler who lives on Selwyn St directly opposite the school.
Mrs Sadler, a 52-year old homemaker, was sitting in her lounge last Thursday around 12.30pm when she noticed a "suss looking" stranger taking photographs of children in the playground.
She watched the pot-bellied man take pictures with a small digital camera from three different angles outside the school fence.
"I thought it was suspicious and I know I should've called the cops ... but I didn't," Mrs Sadler said.
The potentially crucial witness said police had not yet called at her door but was willing to tell them everything she knew.
APNZ reported her sightings to police yesterday.
Mid-South Canterbury area commander Inspector Dave Gaskin today said the investigation was progressing well and he was "pretty confident" it would be solved.
He said Mrs Sadler would be spoken to this morning.
But he raised concerns that she had not come to them earlier.
"We have some concern that the information that she has didn't actually come to the police," Inspector Gaskin said.
"It may not have any bearing at all on the investigation, but it would have been nice to follow it trough before it became public knowledge.
"On Friday we had people speak to everybody in the area and whether she was spoken to her or not ... I can't exactly say.
"She may have been missed, she may not have been home, I don't know, but it would've been really good if she came forward so we could have analysed the information before it got out there."
He confirmed officers had spoken to the boy who was recovering "very well" in Timaru Hospital yesterday and were hoping to chat again this afternoon.
"We had a preliminary chat with him yesterday where we established a rapport with him and we'll be speaking to him over the next few days."
The boy, described as having a dark complexion, of slim build, about 30kg with dark hair, was last seen at 3.15pm on the corner of Luxmoore Rd and Selwyn St. He normally walks home, police say.
On Thursday he was wearing a dark blue polarfleece, dark blue shorts, a teal polo shirt and multicoloured backpack.
He was found at Holme Station Bridge - a 15 minute drive through winding country roads - about 45 minutes later.
Police would not disclose the extent of the boy's injuries, or say whether a sexual element was involved.
Oceanview Heights school has taken extra safety precautions to make sure their kids get home safely.
Extra teachers were posted at the gates for heightened security yesterday and were talking to anxious parents.
