For the best part of a year I investigated the murder of Emma Caldwell, the police's botched inquiry into who had killed her, and a man whom I grew to believe was a prime suspect - Iain Packer.
Packer was always emphatic in his denials to me.
No, he hadn't killed Emma. No, he hadn't raped any of the women who'd claimed that he had. And no, he wasn't a violent man. Far from it, he told me.
"I've not been rough with any woman. I've never hurt a woman in my life," he said. "I can assure you I'm not a violent person."
We met many times, often over coffee. I wanted him to tell me his story and he seemed keen to oblige.
I would investigate him, I said. That's fine, he replied, I have nothing to hide.
The evidence I gathered over the following months built a terrifying picture of Iain Packer:
- allegations of physical domestic abuse, sexual assault, and rape involving a number of different women
- an obsession with Emma Caldwell
- journeys to the same remote woods where her body - naked and strangled - would later be found.
Months after we first met, I interviewed him on camera - twice. The first to listen to his denials. The second to tell him I thought he was a liar.
It all made for the most unnerving piece of television.
"I don't believe you have been telling me the truth," I told him. "All the evidence that I've seen and everything that I have learned makes it clear that you are a sexually violent man, who has raped women. And I think you've got a few hard questions to answer about the death of Emma Caldwell."
Watching the broadcast that night was his former partner. I had met her several times. She was articulate, intelligent, funny and loyal.
Yet court records now show that the day of the second interview, the day I confronted Packer over the evidence I had found, was the day she left him.
And just hours after the broadcast, she found the courage to tell police that he had physically attacked her previously. He had pushed her onto a bed, put his hands around her throat and, according to the charges which were later brought, choked her to her injury and danger of life. He had also stalked her.
He was arrested and charged.
Those denials he had made to me - over coffee, in person, on camera, every time, for months - that he wasn't a violent man began to fall apart, as his three previous convictions for domestic assaults against three different partners were revealed in court.
I often wonder why Iain Packer had agreed to be interviewed by me, bearing in mind that it has now led to his downfall.
I had told him I would investigate everything he shared with me. Maybe he thought I wouldn't dig deep enough.
Whatever his motives, I suspect they are ones he is now deeply regretting.