Bones and parts of a pushchair have been found in a Highland quarry that was drained earlier this month during a fresh murder inquiry into the disappearance more than 40 years ago of a mother and her son.Renee MacRae, 36, and her three-year-old son Andrew, vanished after leaving their home in Inverness on November 12, 1976.Her burned-out BMW was found in a lay-by 12 miles south of the city later that day, with a blood-stained rug in the boot, but their remains have never been found and the notorious case remains unsolved.It emerged on Tuesday that wheels found in Leanach quarry near Inverness are similar to those used on Andrew’s Silver Cross pushchair, which is thought to have been with the pair when they went missing, and are being forensically examined.Bones recovered from silt at the known fly-tipping site are believed to be from animals, but police said the remains would be subjected to further examination.Detective Insp Brian Geddes added: “As part of the search operation at Leanach Quarry numerous items have been found to date, many of which have warranted further research and examination. “Meticulous analysis is now ongoing to establish if any of these items would be relevant to the investigation into the murders of Renee and Andrew MacRae.” leanach quarry pushchair Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily  Front Page newsletter and new  audio briefings. In 2004, a full cold case review resulted in a month-long excavation of another quarry at Dalmagarry.Several days were spent at Leanach Quarry last October, when officers released an image of Andrew around the time of what would be his 45th birthday. A picture of a pushchair was also released.Mrs MacRae left home with both her children the day she went missing before dropping her eight-year-old son, Gordon, with her estranged husband Gordon MacRae, a millionaire businessman.She was reportedly on her way to meet her lover, Bill MacDowell, a married accountant in her husband’s building company, and Andrew’s father. The pair were said to be planning a new life on Shetland. The type of pushchair that went missing with the mother and sonCredit:Police Scotland Work in progress at the drained Leanach QuarryCredit:Andrew Milligan/PA Police Scotland revealed earlier this month that the quarry was being drained of water to allow police to carry out a forensic search of the site.Millions of litres were pumped from the site after it was previously deemed too dangerous for divers to enter.Silt and debris from the quarry is being loaded on to lorries and removed for forensic tests at another location where a 16-strong team of specialist officers are carrying out fingertip searches of the material.The police team said earlier this month they remained “extremely confident” that vital evidence would be recovered from the quarry. After re-examining the case in 2004 police named a suspect in a report to the procurator fiscal in 2006. However, the Crown Office said there was insufficient evidence to bring a prosecution.In November, Mrs Macrae’s sister Morag said she hoped one day to be able to lay them to rest, adding: ‘Not a day goes past that both are not in my thoughts.” read more