Armed officers "forcibly stopped" the car of a man suspected of killing one of Britain's richest men, an eyewitness has told Sky News.
The 34-year-old was arrested in west London - more than 100 miles from where millionaire hotelier Sir Richard Sutton was stabbed to death at his home in Dorset.
A vehicle believed to be linked to the incident was located following "fast-time enquiries", and six police forces were involved in tracking its journey.
Maureen Kane, whose Chiswick home overlooked the road where officers intercepted the suspect late on Wednesday night, told Sky News she heard a car crash and saw armed officers pull a man out of the car.
"About 30 or 40 other police cars arrived and I saw lots of people shouting," she said.
"The man who was in the car was injured - with around 20 policemen around him, shouting 'What's your name?' and then the ambulance came.
"He looked pretty badly injured... He was taken away in an ambulance after being treated on the roadside for about 30 minutes."
She added that armed police had "forcefully crashed the car to make it stop".
Dorset Police has confirmed that the man was subsequently taken to hospital for treatment to injuries that are not believed to be life-threatening.
Sir Richard and a woman - named in reports as his wife - had been attacked during an incident in Higher Langham, near Gillingham.
The 83-year-old was declared dead a short time later, while the woman, aged in her 60s, was airlifted to Bristol's Southmead Hospital in a critical condition.
According to detectives, the arrested man and the victims were known to each other.
A statement from Sir Richard's company said: "Sir Richard was a caring, generous and warm family man, who genuinely regarded those who worked for him as part of his extended family.
"Sir Richard was passionately devoted to both his company and its people, setting the highest standards for quality in the hotel, farming and property interests within the group.
"His loss will be felt by everyone within the company, those who worked with him, and his family who have lost an incredible individual. Our thoughts are with the Sutton family at this tragic time."
According to The Sunday Times, Sir Richard's fortune is worth £301m, making him the 435th-wealthiest person in the country.
He owned the five-star Sheraton Grand and Athenaeum hotels on London's Park Lane.
The entrepreneur had an extensive property and farming portfolio, including the 6,500-acre Benham Estate in West Berkshire and the Stainton Estate in Lincolnshire.