BBC racing commentator John Hunt found his wife and two of his daughters “tied up and shot with a crossbow” when he got home from work.
Carol Hunt, 61 and daughters Louise, 25, and Hannah, 28, were tragically found dead inside their home last night.
After discovering the horrific scene at 7pm on Tuesday, BBC Radio 5 Live and Sky TV correspondent Mr Hunt dialled 999 and police and ambulances raced to the cul-de-sac in Bushey, Herts.
Paramedics and cops tried to save the three victims but they were all pronounced dead at the scene.
Police launched a huge manhunt and tonight a man aged 26 was arrested in a cemetery in Enfield, North London, on suspicion of the triple murder.
Detectives had earlier named former soldier Kyle Clifford as their prime suspect.
He was seen being bundled into the back of an ambulance this afternoon after armed police and paramedics swooped on a cemetery in Hilly Fields in Enfield, North London.
They warned anyone who saw him not to approach but to call 999 immediately.
It is understood Clifford had until recently been in a relationship with younger daughter Louise.
CCTV footage obtained by The Sun showed a suspect walking away from the murder scene with a large object under a sheet.
The man, dressed in black, also carried a bag which he placed in the rear of a Seat car along with a large crossbow-shaped item.
He appeared calm as he made his apparent getaway.
One local said: “You can see clearly from the outline of what is under the sheet that it is in the shape of a crossbow — it’s massive.”
The car was later found abandoned in Enfield, close to Clifford’s family home.
Armed police carried out a swoop at the address as a massive search of the area’s parks and woodland was also carried out.
Around 12 gun cops with dogs burst into the terraced property at 11.30am.
One officer can be heard screaming: “Armed police, come to the door and raise your hands.”
A source said: “It’s a really heavy response — and shocking for everyone to see. They charged in and spent quite a while in the home. It didn’t seem like anyone was there.”
A primary school in the area was also put into lockdown.
Head Jade-Simone Bacon said: “We’ve locked both buildings and just kept the children inside.”
Dog units, helicopters and drones were deployed amid fears Clifford, who served as a Queen’s Dragoon Guards trooper, could use military skills to hide out in the area on the edge of green belt land.
A search of the Hilly Fields Park was carried out as armed officers from the Met and City of London Police joined the hunt.
Cops also scoured Lavender Hill Cemetery with mourners being turned away.
Hertfordshire Police Chief Supt Jon Simpson earlier urged Clifford to give himself up.
Addressing Clifford directly, he said: “Kyle, if you are seeing or hearing this, please make contact with the police.”
Sources confirmed that Clifford had recently broken up with Louise.
She ran a dog grooming business called Groom and Glow from the family’s detached home while sister Hannah had her own cosmetics business.
Neighbours described them as beautiful girls, while one local said Louise was so upset at the recent break-up that she crashed her car.
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.
“So much so that she was driving home at some point last week and drove into a wooden telegraph pole not far from the house.”
Sources said Clifford served for two years with the Queen’s Dragoon Guards, a light cavalry regiment but has now been working in private security.
Mr Hunt and a surviving daughter are being comforted by family and friends.
He was working at a race meeting at Lingfield Park in Surrey on Tuesday before returning home to find the horror scene.
I feel very sad for the family. My heart goes out to them.”
Francis Turner
Yesterday, friends left floral tributes outside the house.
Neighbours told how at least 20 police and ambulance vehicles had descended on the road.
Local councillor Lawrence Brass, who lives 100 yards away, said: “We’re all a bit shell-shocked.
“This is a very traditional, quiet, leafy suburb, we don’t get this sort of thing in this area.”
Francis Turner, who lives nearby, said: “My husband and I were watching the football when we heard sirens and shouting. There were around 30 police outside.
“There were armed police. They came and knocked on our door and told us to stay inside and keep our doors shut.
“I feel very sad for the family. My heart goes out to them.”
Home Secretary Yvette Cooper said she was being kept “fully updated” on the killings and urged anyone with information about the case to contact police.
She tweeted: “The loss of three women’s lives in Bushey last night is truly shocking.
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“My thoughts are with the family and friends of those who have been killed and with the community.”
The Home Office has carried out a review of the legislation on crossbows, which are legal to buy and own but unlawful to have in public without a reasonable excuse.