A retired university lecturer was found stabbed to death at his home in Edinburgh on Saturday morning.

Roger Gray, who was gay, was found in the hallway of his Merchiston flat after neighbours reported a gas leak.

Police said he had been stabbed in a “sustained attack” and are working on the theory that his killer tried to disguise the manner of his death by rigging a gas leak.

He is reportedly the third gay man to have been killed in Edinburgh in the last month.

John Carter, 44, was found dead in a lift in a block of flats on February 27th. He died in hospital several hours later and friends speculated he may have been killed because of his sexuality.

On the same date, a man was found dead in Pilton. The Daily Record reports that the man, who cannot be named for legal reasons, was gay.

Detective Chief Inspector Gareth Blair, who is leading the investigation, said police were appealing for witnesses who may be able to help with the investigation into Mr Gray’s death.

His death is being treated as suspicious by police, who have stopped short of saying he was murdered.

DCI Blair said: “We have witnesses who heard a disturbance within the flat around 10pm on Friday. We are asking residents nearby and anybody who was in the area at that particular time to come forward. They might not think it is significant, but it may be.”

He added: “He has injuries that are consistent with stab wounds. He clearly has been assaulted and we are treating the inquiry as a suspicious death. He has clearly been subjected to a sustained attack.”

Mr Gray retired from Heriot-Watt University in 2007, where he had taught maths and statistics for 40 years.