A pensioner and his sister are being questioned by police after a suspected burglar was shot dead following a break-in at their home.
Reuben and Kathleen Gregory were arrested on suspicion of murder after a man was killed close to their isolated caravan in woodland near to Heathrow Airport.
The pair were said to have called 999 to report a man had suffered gunshot wounds off the Colnbrook bypass near Slough, Berkshire, just before 3.30am on Monday.
Emergency services including armed officers responded to the call and found a victim in his 40s who was pronounced dead at the scene.
Mr Gregory, aged in his 70s, has lived with his sister, aged in her 50s, in what a relative described as a "secluded" woodland for the past 50 years.
The siblings were targeted in a burglary 30 years ago in a break-in during which Ms Gregory was tied up, the family member said.
The female relative, who did not wish to be identified, described them as "very, very quiet inoffensive people who don't cause any problems to anyone".
She added: "They are just very peaceable people, living a very simple life. That's the way they have always lived, that's the only life they know."
Detective Chief Superintendent Chris Ward, of Thames Valley Police, said investigators were treating the shooting as an "isolated incident" as he tried to reassure locals.
DCS Ward said: "I must stress that this incident is not being treated as related to terrorism and there is no threat to the wider public."
He appealed to anyone who saw or heard anything unusual in the area in the early hours of the morning to call Thames Valley Police officers on 101.
