It was a scene of unimaginable horror that left even hardened detectives shaken. A defenceless mother and her two daughters tied up in their own home and shot dead with a 3ft-long crossbow in a bloody rampage.

Around 6.30pm on Tuesday, neighbours of a £800,000 suburban home in a quiet cul-de-sac in Bushey, Hertfordshire, heard piercing screams which were initially mistaken for that of a distressed child.

Later they were to realise that it was a woman's desperate cries for help coming from the home where Louise Hunt, 25, her sister Hannah, 28, and mother Carol, 61, were ambushed by a crossbow-wielding killer.

Soon after the screams fell silent, the assailant fled the property, by which time the police had been alerted and were on their way.

It is believed that on finding his wife and daughters fatally wounded, officers were able to contact BBC horse racing commentator John Hunt, a voice known to millions, who was returning from working at Lingfield Park course.

Although police and ambulance had rushed to the house, they were unable to save the three victims who died at the scene.

But it wasn't long before detectives were on the trail of a suspect after a figure was seen darting out of an alleyway directly behind the murder scene. Clad in black, the man was captured on camera calmly striding away with what appeared to be a crossbow tucked under his arm hidden beneath a white sheet.

Footage from a nearby doorcam showed the bearded figure carrying a heavy bag, which police feared may be a cache of weapons he used to carry out the brutal attack.

Chillingly, he passed within feet of a female neighbour, who stood alone on her driveway stroking a cat and seemed startled by the sight of the barely concealed weapon at 6.50pm.

Within hours, a national manhunt was under way for former soldier Kyle Clifford, who was named by police in a highly unusual step. The 26-year-old had previously served in the Queen's Dragoon Guards for a short time before dropping out having failed to impress superiors, it was said last night.

Yesterday neighbours revealed that Clifford had been in a relationship with the Hunts' youngest daughter, Louise, but she split up with him a week ago.

Their parting is said to have left her so shaken that she recently crashed her car into a telegraph pole outside the family home.

Neighbour Glyn Nicholas, 77, said: 'Louise was a very nice girl. She ran a dog grooming business from the house. I heard that she split from a boyfriend last week and was very upset about it.

'A friend of Louise's told me that her car door had caved in because of the crash.'

He added: 'Carol was a nice, polite and quiet lady. She was at home a lot of the time.

'They were all very nice, a private family. They all did their own things. Louise started a business a couple of years ago, and it was a thriving business – we all took our dogs there to be groomed.

'A very close-knit family and they used to love the street. They'd had a lot of work done on their house over the years.'

Mrs Hunt, a mother of three, had recently told friends at her local gym that her youngest daughter was involved in a 'messy break-up' with her boyfriend.

One suggested her daughter's relationship had turned nasty.

A friend said: 'She said her daughter's split with her boyfriend was messy. Carol did not go into too much detail, but you could see she was concerned.'

Police yesterday warned the public not to approach the suspect, who was last seen driving off from the cul-de sac in a grey vehicle the previous evening.

One neighbour said 'absolute chaos' broke out as armed police arrived. She said: 'It was between 6.30pm and 7pm and it sounded like kids, somebody screaming, and then it was more shrill and I was like, 'That's definitely a woman screaming', and within 15 minutes, it was absolute chaos.

'We had armed police running down, screaming, 'Stay in your house'... they shut us off and basically put us into lockdown.' Police searches predominantly focused yesterday on Hertfordshire and North London because the police did not believe their suspect had the time to get much further.

Passengers arriving at London Victoria railway station during the morning rush hour, before news of the tragedy became public, found their exit slowed as they were unusually marshalled through the barriers, allowing ranks of police on the opposite side to scan the crowd, checking every face.

Later, local schools were put into lockdown when armed police raided the suspect's home in Enfield, North London, some 14 miles from the crime scene.

One mother said: 'They had cordoned off the road and were ushering people away from the house they were going into. They had the full protective gear on, guns, shields and helmets – the kind you'd expect to see in riots.'

Dozens of officers from Scotland Yard and Hertfordshire Police flooded the area a short time later after finding Clifford's abandoned car. But within hours, the hunt had moved to a nearby cemetery just a few minutes' walk away. The former security guard was later found with self-inflicted injuries at Lavender Hill Cemetery just after 4.30pm after seemingly shooting himself with the crossbow.

In a burst of intense activity, armed police closed down the cemetery, as eyewitnesses saw paramedics running into the grounds.

Rae Cresswell, 26, a local who filmed the commotion, said: 'I saw about ten officers coming in. I was quite worried because they were armed and there were dogs with them.

'I asked them if they wanted me to leave but they said it was fine to stay. They started checking the area so I left shortly after and came back to see all these vehicles.'

Around 20 minutes later Clifford was stretchered from the scene and taken by ambulance to Royal London Hospital, where he was receiving medical treatment last night.

Police confirmed no shots had been fired by officers and nobody else was being sought.

Mr Hunt, himself a former police officer before he took up radio and became a much-loved personality on the horse racing circuit, was said to be inconsolable last night. In a note to staff, the BBC said: 'The news today about John Hunt's family is utterly devastating.

'Our thoughts are with John and his family at this incredibly difficult time and we will provide him with all the support we can.'

Julie Harrington, chief executive of the British Horseracing Authority, said: 'The thoughts of everyone at the BHA are with John Hunt, his family and friends. It is impossible to comprehend the horror that has been inflicted upon them by this dreadful event.

'John is a great friend to many in our sport and I am sure that in this time of unimaginable grief for him, the racing family will rally around as we have seen many times before when one of our number is faced with great trauma.'

Last night neighbours and friends continued to lay flowers at the scene. One friend, Su Kehinde, 60, who lives nearby, said she would remember them as 'beautiful souls'. She said: 'They were the loveliest, gentlest family. They did not deserve this. They were beautiful souls.'

Her daughter April, 32, said that Hannah, who worked nearby as a beautician, 'always had a smile'.

She added: 'She was hard-working, a hard grafter and really gentle.'

Six years ago, Clifford's older brother was convicted of murder after a trial at the Old Bailey.

Bradley Clifford, a plumber, was 23 when he mowed down Soban Khan, 18, and Jahshua Francis, 19, on their moped after they struck his 'prized' Ford Mustang car with a bottle.

Both teenagers were flung from the moped by the impact, and Bradley Clifford beat Mr Khan as he lay on the ground injured.

The incident followed a row outside a bar in Enfield in which Clifford's car received superficial damage. He flew into a rage and pursued the pair in a 20-minute high speed chase before crashing into the moped.

Clifford was jailed for life and told to serve at least 23 years for the murder of Mr Khan and attempted GBH with intent on Mr Francis.