For almost half a century, the name of Renee MacRae has occupied near-mythical status as a byword for one of Scotland’s most infamous unsolved crimes.The tortuous hunt to bring her killer to justice began on a wet November night in 1976 when her unoccupied BMW was found ablaze in a Highland lay-by.

Yet, by the time it ended yesterday at the High Court in Inverness, it was clear that the key to cracking this most baffling of cases had lain tantalisingly close at hand from the outset.

Perhaps the greatest surprise in this saga of remarkable twists and turns is that it has taken so long to secure a guilty verdict against the prime suspect in the case.

When Renee’s secret lover, Bill MacDowell, was finally convicted of her murder and that of their three-year-old lovechild, Andrew, his place in Scottish criminal history was assured.He joins the handful of people found guilty of murder in the absence of a body.

In MacDowell’s case, his wickedness extended to killing a defenceless child – his own flesh and blood. Such unfathomable evil has long been compounded by his implacable refusal either to admit his guilt or reveal where his victims are buried in order to allow their relatives and friends a chance to properly grieve their loss.

Now, at least, a jury has ensured the man responsible for their long years of suffering will face a reckoning for his crimes.

At the start of the police investigation, nothing seemed so clear-cut.The first inkling anything was wrong came after a blue BMW 1602 saloon was spotted on fire on Friday, November 12, 1976, meu in a lay-by on the A9 at Dalmagarry, 14 miles south of Inverness.

The burning vehicle belonged to Hugh MacRae & Co, a local building firm and major employer in Inverness, but it was always driven by Christina Catherine MacRae, 36, known as Renee, the estranged wife of company boss Gordon MacRae.

The couple had married in 1963 but, by 1974, they had split up and petite, blonde mother-of-two Renee was living in a luxury bungalow in Inverness, supported financially by her husband, who had taken up with his receptionist, Vivienne.

Unbeknown to him, though, Renee had also fallen for someone at his offices – company secretary Bill MacDowell.

MacDowell was a well-known figure in Inverness long before his name was linked with Renee MacRae.Trim and athletic, he played tennis, squash and badminton and opponents recall a powerful, quick-tempered player who ‘hated to lose face’. One said: ‘He always gave 100 per cent and often smashed his racquet.’

On that fateful weekend, Renee had told her husband she was heading to Kilmarnock to visit her sister, Morag Govans, and was taking Andrew with her while their son Gordon junior, then aged nine, would stay with his father.

Renee would be back in plenty of time to collect him from school on Monday afternoon.

When Gordon was informed about the BMW by police, he phoned Morag and discovered Renee and Andrew were not in Kilmarnock.At first, he was not concerned, as he suspected Renee’s story was a cover because he knew he was not Andrew’s father and had known for years she had a lover, although he did not know who.

He told the police he thought Renee had parked the car somewhere and gone to her destination in another vehicle, so presumed it had been stolen by joyriders.He imagined she would be home by Monday with Andrew, but when neither turned up, the worry set in and a search was launched.

As police sifted for clues to her whereabouts, they lifted the lid on a hidden world of middle-class infidelity in the 1970s Highlands, where the MacRaes and the MacDowells crossed paths.

They moved in the same social circles, attending the same parties – one picture from this time shows Renee and MacDowell’s wife, Rosemary, at a New Year party.

By then the secret, extramarital affair was in full swing – in fact Renee may already have been pregnant with MacDowell’s son.

Andrew was born nine months later in 1973.Even when Renee moved out of the family home and into the bungalow, she told her husband nothing about the identity of her lover.

The only person let into this secret – and the truth of Andrew’s parentage – was her best friend and confidante Val Steventon.

Mrs Steventon knew many more of her friend’s secrets.She knew a besotted Renee had been quietly packing everything in her bungalow in the belief that she would be moving to Shetland with MacDowell later that month.

She knew that, on the weekend of her disappearance, her friend had not been on her way to her sister’s in Kilmarnock, as she had told friends, but had plans to meet her lover, who had insisted she take little Andrew along so he could get to know him better.

When Renee had failed to show up three days after her burning car was found, Mrs Steventon told the police everything she knew, fearing she might never see her friend alive again. She hinted at the volatility of the affair, later recalling her last words to her friend were: ‘Have a nice weekend Renee, no fighting.’

MacDowell had to admit to the police that he was Renee’s secret lover, and Andrew’s father.Gordon MacRae, devastated and embarrassed, promptly sacked him.

MacDowell told police that although the couple had a tentative arrangement to spend the weekend together, it was never confirmed and he had decided not to go. He denied any plan to move to Shetland with Renee or that he had secured a job or house there.

What is clear is that by the time Renee disappeared, her long affair with MacDowell had come to a make or break point.

Mrs Steventon recalled: ‘He really took Renee in completely.She even packed up everything. Things were getting a bit hot for MacDowell because little Andrew was starting to point at him and call him Daddy. I think he knew Renee was getting very involved with him, more than he was with her.’

Some believed she had threatened to reveal he was Andrew’s father unless he left his wife and lived with her.He was motivated, detectives now believe, by the fact he had a comfortable lifestyle and stood to lose everything if the affair became public knowledge.

Events became increasingly dramatic after it emerged MacDowell had gone to police the month after Renee and Andrew vanished to give them ‘significant’ information. A police source revealed the accountant had seemed ‘very upset’ but his furious wife spotted his car outside police HQ and removed him from the building before he could complete his statement.Detectives were frustrated, believing it may have been his time to talk about his involvement.

MacDowell only gave one media interview, days after the police investigation began, in which he admitted he was Andrew’s real father and claimed he had ended the affair, that Renee was still alive and that, bizarrely, he was receiving coded telephone calls from her, although she never spoke.

Asked by a Glasgow Herald journalist if he had mentioned this to police, he said it must have slipped his mind.

Meanwhile, a routine missing persons inquiry hardened into a full-blown murder hunt that was gripping the public imagination, although early blunders and delays hampered the police’s best chance of finding the killer.

In the burnt-out shell of the BMW, since destroyed, the only hard evidence was a bloodstain the size of a half-crown found in the boot which matched Renee’s type.It is thought the fire brigade’s hoses washed away what other evidence there may have been. However inconclusive, the blood spot was the first clue to foul play.

An episode of the BBC Current Account programme, first aired on November 26, 1976, and shown in court, gave a flavour of the ‘mystery of the A9′ and the early confusion in police minds about what they were dealing with.

Donald Henderson, the then chief constable of Northern Constabulary, told the programme: ‘We’ve got no idea if a crime was committed.There was a clandestine association involved. When people are involved in a clandestine association you get deceit.’

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