Expert warned against wrist X-rays used by AFP to prosecute children as adult people smugglers

Last week, six Indonesian boys won a major case overturning their convictions as adult people smugglers in 2010 amid the highly charged political atmosphere around border protection.

The children, then as young as 13, were prosecuted and jailed using analysis of X-rays of their wrists, which police said proved they were adults. A trove of documents attached to their cases, seen by Guardian Australia, shows the boys all repeatedly told navy, immigration and police members they were children, which should have seen them sent back to Indonesia under federal police policy.

Police instead took the dates of birth they provided and altered the year to make their ages align with the wrist X-ray evidence, placing the new dates on sworn legal documents.

The radiologist Dr James Christie began to appear as a defence expert witness in similar people smuggling cases after the six boys were convicted in 2010.

His evidence warned that wrist X-ray comparisons were never intended as a means of assessing age and that the key reference tool on bone development police were relying on had no data on Indonesian populations.

Christie was shocked when police continued to use the technique.

The radiologist said prosecutions failed in cases where he and another witness, a statistician from the UK, gave evidence for the defence.

The Australian federal police were contacted for comment. They declined to respond due to ongoing court proceedings.