A FORMER University of York student who disappeared shortly before his wife and baby daughter were found murdered at their home in Massachusetts is not a suspect, according to British police.

A statement from Nottinghamshire Police said: "Neil Entwistle is not a suspect. He is being treated by the US authorities as a potential witness.

"There are no extradition proceedings in relation to him.

"On that basis, the police in England and Wales have no legal powers to take executive action. In the circumstances, it is not our role to comment on speculation regarding his whereabouts."

Four American plain clothes officers boarded a plane for England yesterday as part of the probe into the murder of Mr Entwistle's wife, Rachel, 27, and their baby daughter, Lillian. The couple met when they were in the rowing club at University of York.

The police officers boarded an Aer Lingus flight at Logan International Airport in Boston, Massachusetts.

A spokeswoman for the Middlesex District Attorney's office would not confirm or deny the reports.

DA Martha Coakley said her office was looking at every possible angle, no arrest warrants had been issued, and that investigators had been in touch with Mr Entwistle by telephone.

She said: "At this time, Neil Entwistle remains a person of interest to this investigation. No one has been ruled in and no one has been ruled out as a suspect in this investigation."

A spokeswoman refused to comment on allegations that Mr Entwistle, an unemployed computer technician, ran a website offering "get-rich-quick pyramid schemes'' linked to internet pornography.

Mr Entwistle's car was found at Logan International Airport and flight records show he bought an air ticket to London 48 hours before the bodies of his wife and nine-month-old daughter were discovered at the family home in Hopkinton, Massachusettes, on Sunday.

There was so little blood on the bed that at first officers thought they had died of carbon monoxide poisoning, but later found bullet wounds from a small-calibre weapon.

The bodies were discovered a day after friends and family turned up for a dinner party only to find the house in darkness.

Mr Entwistle's father, Cliff, a coal miner and Labour councillor for Worksop East, and his mother, Yvonne, were not available for comment.

Mr Entwistle's brother, Russell, was believed to have travelled from his home in Leeds to join them yesterday.

Mr Entwistle graduated in 2002 with a degree in electrical engineering from the University of York, where he met Rachel, who was studying for a PGCE teaching qualification.

After graduation, Mr Entwistle worked in the Malvern office of QinetiQ, a high-tech technology supplier to the Ministry of Defence, but he resigned in July to move to the US with his wife and daughter.

Updated: 09:40 Friday, January 27, 2006