THE father of a murdered book-keeper has spoken of the family's continued agony in not knowing where her body is, as he gave his first interview since the conviction of his daughter's killer.

Suzanne Pilley, 38, was murdered by her colleague and former partner David Gilroy as she made her way to work in the centre of Edinburgh in May 2010.

Gilroy, who is believed to have hidden her remains in a remote area of Argyll, is due to be sentenced at the High Court in Edinburgh today.

In an emotional television interview to be broadcast on the BBC tonight, Rob Pilley, 68, of Stenhouse, Edinburgh, described how life has not been the same without his daughter and how he instinctively knew something was wrong when she disappeared.

Mr Pilley said the family were kept closely involved as police carried out six searches of land where they believed her remains had been hidden in a "lonely grave".

He said: "They've had us up to Argyll, showed us places where they possibly thought Suzanne may have been buried, different parts, all over Argyll. And, I mean the forests are enormous - it's like looking for a needle in a haystack.

"It's just trees and all you see is a wee hairline crack going through the trees. You don't realise that it's actually a road that's going through there and Suzanne could be in any one of those roads.

"You've always got your hopes up."

Gilroy, 49, was convicted by a majority verdict following a 17-day trial at the High Court in Edinburgh. The prosecution argued that Gilroy killed Ms Pilley because she tried to break off their two-year relationship. The sentencing today will be filmed at the High Court after Gilroy's plea in mitigation has been heard.

Mr Pilley said waiting on the verdict was "the worst three days of our lives". He said: "You know what decision the family's made, but it's a case of, 'has the prosecution got the message across to the jury?' You just hope and pray, that he has."

After the conviction, Mr Pilley said he felt as if "a big heavy load had been taken off my shoulders".

He added: "I just feel, the door's open, was open. After the trial it's ajar, and hopefully one day we'll be able to close the door".

Asked what message he had for Gilroy – or anyone else who has information as to his daughter's whereabouts – Mr Pilley said: "I'd just like to say there's a lot of parents out there that know where their children are, and where they'll be sleeping tonight, but unfortunately my family doesn't know where Suzanne's sleeping."

In the BBC programme, Mr Pilley said his daughter was "always happy go lucky, she was always on the go".

Asked about the last time he had contact with her, Mr Pilley said: "I had just picked her up at the shops. I was the last one to see her in the family.

"I'd picked her up from the shops with her messages ... and I dropped her off at the stair. At the time, I was waiting on getting operations done to my legs, and so I couldn't help her up the stair with her messages.

"And she just gave me a wee peck on the cheek. And that was the last I saw of her."

The retired HGV mechanic also spoke of how he knew something serious was wrong when his daughter first went missing.

"It was just probably instinct, I think," he said. "It was just so unlike Suzanne not to be in touch, I knew something sinister must've happened."

Suzanne Pilley: The Woman Who Vanished, is on BBC One Scotland at 10.45pm tonight.