A Kosovan immigrant wanted over the brutal stabbing of a pensioner and the disappearance of his elderly wife fled to France the day after his body was found, according to police.
Forklift driver Ali Qazimaj went on the run after Peter Stuart, 75, was knifed to death and his wife Sylvia, 69, went missing.
The 42-year-old, who goes by the name Marco Costa, caught a ferry from Dover to Calais around 24 hours after Mr Stuart's body was discovered in woodland in Weybread, Suffolk.
He is believed to have boarded the boat alone and on foot at around 6:30pm on Saturday 4 June.
Detective Chief Superintendent Simon Parkes said: "We strongly believe that finding Ali Qazimaj will help us in locating Sylvia, who has now not been seen for nearly 10 days.
"We know that he was living in Tilbury in Essex and that he has been working in Purfleet as a forklift driver.
"We believe he is from Kosovo, that he sought asylum following the conflict and was granted this and given a British passport. We also know he has used the name Marco Costa.
"We urgently need anyone who knows him, who may have spent time with him over the last few weeks or before this to get in touch and tell us more about his background so that we can trace his movements.
"We are particularly keen to hear from anyone who may have seen him between Sunday 29 May and when he left the country on Saturday 4 June, or anyone who can shed light on where he may have been between these times."
Mr Qazimaj was granted asylum in Britain during the 1990s during the Yugoslavian war and lived in the Thurrock area of Essex.
His car, a silver Citroen C3, was found near the ferry terminal in Dover at around midnight on Sunday. The vehicle has been searched and will be forensically examined.
Members of the public are warned not to approach him but to call 999 immediately if he is seen.
Mr Qazimaj is described as white, around 5ft 6in, with brown eyes and dark brown, greying hair. He was last seen on Friday June 3 in Essex, the same day Mr and Mrs Stuart were reported missing.
Mr Stuart's body was found in woodland that evening, close to where the couple lived in Mill Lane, Weybread, with a number of knife wounds.
The last time the couple was seen alive - on Sunday May 29 - has been captured on CCTV footage.
They can be seen together walking into Goodies Farm Shop in Wood Lane in Pulham Market at around 10.20am.
Police are appealing for anyone who saw them that day, or leading up to Friday June 3, to come forward.
A 61-year-old man from Leicester who was arrested at around 8.30am on Sunday has been released on bail and is due to return to Martlesham Police Investigation Centre on August 3.
Anyone with information can contact Suffolk Police through the incident room on 01473 782000.