The man accused of murdering Renee MacRae and her son more than 45 years ago has said her estranged husband, along with others, was responsible for the crime, a court has heard.

William MacDowell, of Penrith, went on trial at the High Court in Inverness on Tuesday where he is accused of killing the 36-year-old and her son Andrew, three, in November 1976.

Represented by Murray Macara KC, the court was told the 80-year-old denies the charges against him and has lodged a special defence of incrimination and alibi.

The jury of seven men and eight women were told he was not at the scene of the alleged murder on November 12 1976, and that he spent the night at home.

The defence claims that Ms MacRae’s husband Gordon MacRae, whom she was separated from, committed the offences together with persons unknown.

MacDowell, who appeared in court in a wheelchair, is charged with assaulting Ms MacRae and her three-year-old son at the Dalmagarry layby on the A9 trunk road, or elsewhere, by means unknown, and as a result murdering them.

READ MORE: Renee MacRae murder accused to face trial next year

He is also charged with disposing of their bodies and belongings by means unknown.

MacDowell is also accused of setting fire to a BMW car, disposing of a pushchair, and of a boot hatch from a Volvo, and that he did so to avoid detection, arrest, and prosecution.

Advocate depute Alex Prentice KC is prosecuting, and Lord Armstrong told the jury that he expected the trial to last about four weeks.

The court was told Mr MacRae married Renee MacRae on May 17 1963, but they split in 1975. The court heard that in the July of the following year, she moved into Cradlehall Park, near Inverness, in a home provided by her estranged husband.

The trial continues.