A man from London has been arrested on suspicion of murder in connection with the disappearance of a pensioner.
Thames Valley Police said 70-year-old Samuel Alexander (pictured) has not been seen since he went missing from Prospect Place in Drayton Parslow in August last year.
Police are continuing their enquiries at his address.
Det Ch Insp Joe Kidman, investigating said: "Officers have arrested someone in connection with Mr Alexander's disappearance.
"However, this is one element in a large investigation to find a man about whom we have very serious concerns.
"I would ask anyone who may be able to assist us with the whereabouts of Mr Alexander since August 2009 to come forward."
Mr Alexander, also known as Sami Yacoub El-Kayoubi, has receding grey hair, dark eyes and occasionally wears glasses.
He has olive-coloured skin, is of slight build and walks with a stoop, possibly aided by a walking frame.
He usually wears neutral, plain shirts and trousers.
Mr Alexander is originally from Egypt and has lived in England for many years.
If you have any information call 0845 8 505 505, quoting URN 1467 of February 6, 2010, or call Crimestoppers, anonymously, on 0800 555 111.
A 22-year-old man from London was arrested on suspicion of murder on Friday, February 5 and is currently in custody at Aylesbury police station.