The Scouts were rocked when he came clean about the police inquiry into his online debauchery. His membership was immediately terminated.
Scouts regional development manager Chris Wilson said there had never been an issue with Sawtell's behaviour during his involvement.
"No complaints, no concerns ... absolutely nothing," he said. "As an organisation we were shocked and disappointed to learn that a person with such a positive standing had been offending in such a manner."
Wilson said a senior volunteer at Scouts had spoken to Sawtell, who stressed none of the children had been physically harmed.
A Canadian investigation into an anonymous messaging app uncovered Sawtell's crimes. A profile traced back to him - "waterbaby1986" - was found to be trading lewd images with another user.
From there, New Zealand police executed a search warrant at Sawtell's Mosgiel home.
Analysis of his cellphone revealed he had pretended to be a 13-year-old to entice other app users to send images of themselves.
But the true depth of his offending lay in a cloud-based account bearing 5420 files. Police took a random sample of 3626 and more than 1100 were discovered to be illegal.
Judge Michael Turner warned the public in court yesterday that details would be "disturbing".
Some videos involved children as young as 2, others showed pre-teens violated by adults and performing sex acts on animals.
