When Amy Smith’s husband was charged with horrific historical sex crimes, she launched an extraordinary bid to prove his innocence.

Ben Smith, a hardworking former NSW Police officer and then Crime Commission investigator, had his life turned upside down in December 2016 when he was called into his boss’ office for an emergency meeting.

There he was told he was under arrest for historical acts of indecency and non-consensual sexual intercourse with a minor.

The charges dated back to when Smith had moved to Sydney as a 16-year-old to play rugby league.

He was billeted to a local family, where he and the woman who would later become his accuser were like “brother” and “sister”.

“I was just another member of the house — that’s all that it was,” he told 60 Minutes.

Ben Smith had not seen the woman, who cannot be named for legal reasons, for 15 years at the time of the complaint — and he had evidence to prove the accusations were not true.

Former NSW Police officer Ben Smith. Photo / 60 Minutes

“I pretty much dismantled probably 70 per cent of the fact sheet,” he said.

That’s when Amy took charge, setting out to do the detective work they alleged the police hadn’t — tracking the paper trail of her husband’s life to cross-reference and test the allegations.

“You’re told you don’t have to prove your innocence, it’s the prosecution’s job to prove guilt,” she told the programme. “But, a 100 per cent, to be able to provide all of this factual, actual hard evidence … for me, it was empowering.”

In addition to Amy’s forensic work, another witness also refuted the woman’s claim that he had seen Ben Smith indecently assault her.

Ben Smith faced two trials, the first ending in a hung jury. At the second, he was unanimously found not guilty.

But the couple are now seeking accountability from NSW Police over the ordeal, which Ben Smith says has ruined his reputation, career and financial future.

They believe in the MeToo era, police have failed to make basic inquiries to test allegations for fear of being accused of not believing victims.

“We don’t want to come across as people that are anti people making complaints,” Ben Smith said.

Amy added, “There are victims out there, and they should not be afraid to make their complaints. But when you have people that don’t do their job properly, that’s a hard pill to swallow.”