Four people aged between 18 and 53 have been arrested on suspicion of his murder.
Police have launched a murder investigation into a farmer who has been missing since June.
William Taylor, 70 – known as Bill – of Gosmore, North Hertfordshire, was last seen at his home on Sunday June 3 at about 9pm, shortly before his 70th birthday, and reported missing the following day.
Four people were yesterday arrested (September 19) on suspicion of conspiracy to commit murder, arson and conspiracy to commit arson.
The three men aged 18, 22 and 53 and a 52-year-old woman, all from Hitchin, were connected to a vehicle fire at Mr Taylors home on May 27.
They have since been released on bail.
Detective chief inspector Carl Foster from the Bedfordshire, Cambridgeshire and Hertfordshire Major Crime Unit, which is leading the investigation, said: “Extensive enquiries and searches have been carried out since William was reported missing, including a thorough search of the farmland surrounding his home.
“William’s body has not been found and our inquiries are continuing.
“Understandably this is an extremely difficult time for his family and they have asked for their privacy to be respected.”
William is 5’11" tall, average build and has short grey hair. He was last seen wearing a blue long sleeved shirt, denim jeans, black wellies or possibly a navy boiler suit.
Anyone with information has been asked to contact the police using 101, or through this link.