The child had been beaten around the head and was so shocked that he was unable to say anything to police about the attack on Wimbledon Common in south-west London. It is thought that the 22-year-old woman may have been raped.
Police think it is possible that the killer grabbed the boy and dragged him into the wood, forcing his mother to follow. He was then able to attack her with less likliehood of being seen.
The murder victim had not been formally identified last night but she was blonde and came from south-east London. She drove a silver Volvo to the common. Scotland Yard is not planning to release her identity until later today although it is thought that police have been in touch with her family.
The woman's throat had been cut and a post-mortem examination revealed last night that she had died from multiple stab wounds in what detectives described as a frenzied attack.
The murder happened just before 10am in a thickly wooded area about 200 yards north-west of the Windmill, a local landmark. Hundreds of walkers, golfers, cyclists and horseriders were on the common at the time.
An elderly man found the boy clutching the body of his mother, who had been partially stripped, a few yards from a footpath. He took the child to the club house of the London Scottish Golf Club where a tournament involving more than 100 players was taking place.
The child was taken to a local hospital and was being looked after last night by a woman police surgeon and a woman police officer. He had not been sexually assaulted but had suffered bruising to his head. A Scotland Yard spokeswoman said: 'He is in hospital. I understand that he has been treated for shock and that his physical injuries are not serious.'
Detective Chief Superintendent John Bassett, who is leading the murder hunt, said: 'He is having difficulty speaking to us because of the shock of what has happened. He is in deep shock.'
The woman's black mongrel dog was found wandering near by. It had an address tag on its collar which provided police with an early clue to her identity.
Police are looking for a man wearing a T-shirt and jeans seen running away from the area. They are also checking reports that a man was seen near by washing blood from his hands in a stream.
An appeal for anyone who saw a man acting suspiciously to come forward was made last night. The spokeswoman said: 'He would have been heavily bloodstained. Anyone who can help should call police on 081 947 1212.'
It is thought that the motive for the attack was sexual, as the woman's trousers had been pulled down during a fierce struggle. The common is a haunt of men who expose themselves to women.
Detective Chief Inspector Michael Wickerson, who has been a policeman for 26 years, said: 'It is the worst murder I have ever seen. This was an unsuspecting woman walking with her two-year-old son and dog in one of the nicest parts of London.'
His shock was shared by people who live around the common, where the last murder took place more than 20 years ago. Until yesterday it provided a safe place to escape from the noise and traffic of London.
One walker said: 'It is a lovely place but I think that people will be very wary of coming here now. Women certainly should not come here alone and it is very sad that they won't be able to do that.'Reuse content