A middle-aged couple died in a "sustained" and "violent" attack in their home in the middle of the night in a leafy rural village.
The husband and wife, who police believe are Patrick and Gillian Kettyle, were stabbed to death in the quiet Surrey village of Fetcham.
Lithuanian builder Viktoras Bruzas, who was wanted on suspicion of the murder, has been arrested, Surrey Police said tonight.
Police search an area near where a knife was found in a road that leads to a house where a couple have been found stabbed
The couple, who are in their 50s, were found at 12.30am today by a member of the family, believed to be one of their teenage children.
A second man in his 30s was arrested in Walton-on-Thames this morning on suspicion of conspiracy to commit murder. He has since been bailed, pending further inquiries.
Kettyle is listed as the managing director of building development company Kettyle Ltd, which has been running for 29 years. Its registered address is the family home.
A neighbour walking her dog said she thought he had inherited the company from his father.
Post-mortem examinations will be carried out on the couple tomorrow and formal identification will follow. Mr May added that the family member who found the bodies was unhurt in the attack.
At the scene in the quiet village near Leatherhead, full of large, detached houses in extensive grounds where retired people live side-by-side with commuters to London, police and masked forensics officers spent the day scouring the Kettyles' two-storey home for clues.
Two cars, a black Audi Q3 and a red Fiat 500, sat on the brick-paved drive next to neat bushes.
Much of The Copse was cordoned off with police tape throughout the day, with yellow police evidence markers at various points up and down the street.
Officers also carried out a fingertip search of Meadow Way, checking gardens, and hedges, emptying household bins and even probing building work in a front garden.
Shocked residents stood out in the streets discussing the incident with each other and officers who manned the cordons.
A number of them said they often saw Mr Kettyles to say hello to when he was out walking his dogs, and described the family as being close and as "very nice, very friendly" people who kept themselves to themselves.
A neighbour of the Kettyles said she thought she heard the couple's two dogs barking during the night around the time of the incident.
The woman, who asked not to be named, said she heard loud barking and a man's voice trying to quieten them down around the time of the incident.
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She said: "My husband came back late last night from Heathrow and got in at about 11.30pm or midnight.
"A while after he nodded off there was lots of frantic barking going on. He thought it was about 1am.
"There was a huge amount of barking, like a couple of dogs barking at something, and it seemed to go on for quite a long time.
"More importantly, it went quiet, then about 20 minutes or so later what I thought were the couple's dogs started barking.
"They must be in a kennel in the garden, and I thought I heard someone come out and tell them to be quiet.
"It was a man's voice, saying 'Quiet', and the dogs carried on barking for quite a while after that.
"You see it on TV and you don't expect it to happen where you live. It is meant to be one of the lowest crime places in the country, someone told me."
One woman out walking her dog said she thought the couple lived at the house with a teenage son around 16 years old, and that she believed Mr Kettyle had other children from a previous marriage.
She said: "I think he inherited a building company from his father and works from home a lot. Another elderly neighbour said:
"It is just a very sad event, anywhere, but it is a quiet neighbourhood. A lot of the people have been here a very long time.
"Fetcham is probably a commuter area. Any property around here is probably expensive because an awful lot of people work up in London, but also quite a few people are retired and have lived here a long time, which is my situation.
"We would think it is a very safe community. I can't remember anything like this ever happening around here. This is all a bit of a surprise."
Raj Haque, a Liberal Democrat councillor for Fetcham West, added: "This news has come as a huge shock and a big surprise to all of us in the village.
"Something like this tragedy has never happened within this area.
"As soon as the culprit has been caught it will be a big sigh of relief for the village."
Anyone with information about the incident is asked to call Crimestoppers on 0800 555 111.