Police investigating the shooting of a Wandsworth builder are making an appeal on BBC Crimewatch tonight.

Builder Stuart McMahon, 45, was murdered at his home in Magdalen Road on September 29 last year.

It is believed the father-of-two was deliberately shot rather than killed in a robbery gone wrong. Detectives said it was possible Mr McMahon knew his killer or killers.

Det Insp Andy Redwood said: "We are also able to reveal that the firearm used was a .22 weapon - a very unusual weapon to be used in a murder.

"Stuart died in the kitchen, which means he must have staggered from the front door down the hallway.

"The glass was broken around the lock areas on the door and the attacker may have broken in to make sure Stuart was dead," he added.

Shots were fired into the door shattering the glass pane and police found empty cases suggesting the killer fired six shots.

Mr McMahon had been renovating the house and had just exchanged contracts on its sale.

His body was discovered by local officers around 5pm on Saturday, September 30, who were called by a neighbour who noticed a glass pane in the front door was shattered.

Mr McMahon had been decorating a property with a friend who dropped him home and came in for a cup of tea on Friday, September 29.

After that, it appears he called a friend to make an arrangement to meet later that night. He changed his clothes, turned on the television and started to work on some correspondence.

Previously, detectives estimated that Mr McMahon was shot some time between 7pm on Friday, 29 September and 4.30am the following day. Now, they say the shooting happened between 9.30pm and 9.40pm on Friday.

Police are also trying to trace the owner of a silver earring found at the scene.

Detectives are keen to find an unknown black man seen arguing with Mr McMahon outside his house several days before his death.

Mr McMahon was a self-employed builder and property developer. He had been separated from his wife for four years but was still on good terms and regularly saw his two teenage daughters.

Crimewatch is on BBC One at 9pm.