Police searching for a retired university lecturer missing for six months have found human remains in his garden.
Samuel Alexander, 70, was last seen in August 2009 near his home in Drayton Parslow, Milton Keynes, Buckinghamshire, but was only reported as missing last week.
A 22-year-old man, whom neighbours named as Mr Alexander's son Mark, was re-arrested on suspicion of murder last night after the remains were discovered and is in police custody.
He had been previously arrested and bailed in connection with Mr Alexander's disappearance.
Thames Valley Police said it was too early to confirm if the remains were those of Egyptian-born pensioner Mr Alexander. Officers are continuing to search his home today.
Police would not confirm the identity of the arrested man, who is from London.
Mr Alexander, also known as Sami Yacoub El-Kayoubi, was reported missing by concerned neighbours in Prospect Close who realised they had not seen him since last summer.
A Thames Valley Police spokesman said: "He is a private man and has always kept himself to himself, which is maybe why it didn't occur to them to report his disappearance sooner."
He described Mr Alexander, who taught English at De Montfort University in Buckinghamshire, as "quite frail" and said he often walked with the aid of a frame.
Neighbour Ed Clampitt, 17, said he last saw Mr Alexander when he was building a wall at the rear of his detached home to cover up his garden.
He said: "I did register the fact I'd not seen him around, but I thought it was because it was winter and it was colder.
"This whole thing really is bizarre. There was always something odd about the place though."
He said Mr Alexander's son is studying law at King's College London but left his car at his father's property.Reuse content