NEIL Entwistle appeared a loving family man, but lived a sordid hidden life of deceit, searched sex websites looking for adulterous affairs, and was thousands of pounds in debt.

A series of failed internet porn scams led to him desperately trawling the web for "1-on-1" relationships with American women and tips on how to commit suicide in the days before killing his wife and baby daughter.

Widely known as an intelligent, likeable man with a young happy family, Entwistle kept his murky world of internet sex and financial troubles largely secret from his family and friends.

A Walter Mitty figure, Entwistle was a shy and reserved Briton, who harboured a secret life which led him to murder his wife and baby daughter with his father-in-law's gun.

And he even convinced his in laws he was working as a British Secret Service agent as he took out a £1,350-a-month lease on a Colonial-style four-bedroom home at 6 Cub's Path in Hopkinton, Massachusetts with no visible means of support. Just 10 days later the bodies of his wife and baby daughter were found.

Born on September 18, 1978, Entwistle is the son of school dinner lady Yvonne and Bassetlaw district councillor Cliff and was one of the highest achievers in his year at Valley School, Worksop, Nottinghamshire, where his name adorns an honours board in the school hall.

He left to study electronic engineering with business management at the University of York, where he met Rachel, an American student on an overseas placement. During a visit to his old school with Rachel, he introduced her as "the person I'm going to spend the rest of my life with".

Before the couple's wedding in Plymouth, Massachusetts, in August 2003, Entwistle wrote on the Friends Reunited website: "Getting married to the most amazing woman in the world this summer." He went on to speak about his work with QinetiQ, a leading defence technology and security company, and said: "Making bombs and other stuff for a living – would tell you more but I'd have to kill you." In the autumn of 2005, they moved to the US to pursue their American Dream and to be closer to his wife's family in Carver, Massachusetts.

They lived with Mrs Entwistle's family at first before settling in to their New England home, which was set in a small, family oriented development surrounded by woods and near a country club an hour's drive west of Boston. It came complete with a professional "welcoming lady" whose job it was to make sure the young couple settled in well.

Entwistle paid $8,100 (£4,050) in certified cheques for a three month lease after being refused a six month period because of credit problems, and bought thousands of dollars worth of furniture with credit cards.

He also used cards to pay a $500 (£250)-a-month lease on a BMWX3 car.

There were other credit card debts in England and Mrs Entwistle owed more than $18,000 (£9,000) in student loans.

US prosecutors said the debts were not a "huge amount", but he was jobless and had no visible means of support. Still, the jury heard they believed the couple moved to the US to be closer to Mrs Entwistle's family, and not to run away from his debts.

Entwistle told US investigators he was dissatisfied with his sex life in the days before killing his wife and baby daughter in their Boston home and used a website to email women, saying he was looking for a discreet relationship with someone who was good in bed. He looked up escort services and other websites offering help finding sexual partners in the area.

Through another website, which bills itself as "the world's largest sex and swinger personals community", Entwistle sent a series of emails to American women, saying he was looking for more fun in the bedroom.

His defence team prevented prosecutors from showing the jury a photograph from his Adult Friend Finder homepage. It allegedly showed him naked on an outdoor lounge chair, but his lawyers insisted it did not show their client.

Just three days before the murders, Entwistle searched the internet for information about suicide, euthanasia and "killing people with a knife".

Rachel's mother Priscilla Matterazzo told US police she believed he was an undercover agent because he was so secretive about where his money came from. She said the secrecy "caused conflict" with Rachel. His wife told her mother their money "apparently had been tied up in offshore accounts which Neil would not talk about".

A month after his arrest, District Attorney Martha Coakley told CNN her impression of Entwistle, like everyone else including his in-laws, was that he was a very likeable man. "That is, I think, part of what makes this, in some ways, so sad and somewhat inexplicable, but, also, why people are so interested in it," she said.