Police still have no idea who forced their way into the house of an Earlsfield millionaire builder at the weekend to assasinate him.

After combing the large house and grounds at 8 Magdalen Road all week, the man leading the investigation into the murder of Stuart McMahon said police had no motive, no witnesses to the shooting, and had found no murder weapon.

Detective Chief Inspector Steve Richardson, from the specialist crime directorate at the Metropolitan police, said police had ruled out burglary and there was nothing to suggest Mr McMahon, 45, had any involvement in serious crime.

He said: "At this moment we have no clear idea of a motive but we can rule out burglary. The house has not been ransacked. There is no doubt that somebody came to his house with the intention of killing him.

"Mr McMahon was not involved in serious crime. He was not a gangster. The key to this lies in his circle of associates."

Police believe Mr McMahon was murdered between 4.30am and 8.30am on Saturday.

His body was discovered by police at 5pm on Saturday. He had suffered multiple gunshot wounds and was found in a downstairs room - although police refused to give details of where on his body he was shot and in which room.

Neighbours alerted police after noticing the front door open and smashed glass scattered outside the large red-brick semi-detached house.

Police confirmed that the door had been damaged by gunshots but would not confirm whether the killer had blasted his way in.

A postmortem, held on Monday afternoon at St George's Hospital, Tooting, could yield more clues.

DCI Richardson said: "We are appealing for anybody who knew him, or anybody in the vicinity who was aware of an incident at 8 Magdalen Road to come forward."

A neighbour who asked not to be named said of Mr McMahon: "He was a jolly neighbour. He'd always say hello and ask you how you were you couldn't say anything bad about him. He was a Chelsea supporter and my husband got on well with him."

"We're quite shocked. It unnerves you when something like this happens on your own doorstep," she added.

Anyone with information should contact police on 020 8721 4054 or ring Crimestoppers anonymously on 0800 555 111.