ABC, who soon sold them on to a group they assumed was AQAP.

They were held for four months while their captors negotiated their ransom.

While they waited, they carefully observed their captors.

One, they soon realised, came from a long way away.

"There was one person who was speaking English with a New Zealand or Australian accent so it was very evident that he was not an Arab guy," Mrs Kaleva said.

And even though the guards usually kept their faces covered, Mr Kaleva noticed the man with the antipodean accent had chestnut hair.

One day that particular guard offered them a book to read, and between its pages they found a single hair.

Carefully they hid it away, and took it with them when they were released.

"We gave half to the Austrians andhalf to the Finnish authorities," Mr Kaleva said with a smile.

"But I should have known that the DNA is stuck in the part of the hair that is attached to your scalp.

"So the Austrians got the one with the DNA and the Finns got the one with zero DNA."

But it was enough.

'I felt sad that he was dead'

On the strength of the Kalevas' impression that the owner of the hair was an Australian or a New Zealander, the DNA profile that the Austrians extracted from the hair root was sent to the AFP, who matched it to a DNA sample they already had of Christopher Rosser Havard.

This part of the story is confirmed by heavily redacted documents released by the AFP following freedom of information requests last year.

AFP