A Suffolk man has murdered his wife and killed himself after receiving an anonymous letter in the post that his partner was having an affair.

65-year-old Richard Pitkin and 58-year-old wife Sarah, of Stowmarket, had been married for 37 years, but were separated at the time of the deaths. She was visiting Pitkin to "talk about finances" the Mirror reports. The couple have four children, one of which found a note left by Pitkin after the murder. "Please do not come in. Call the police and say I am sorry they have to deal with us," the note said.

Sarah was killed by multiple stab wounds to the neck and husband Richard committed suicide by hanging himself.

The original letter that alleged the affair was sent to their house in January. Sarah moved out to live with her mother shortly after and was murdered in late February.

Detective superintendent David Cutler confirmed the note was written by Mr Pitkin. "It gave details of his thoughts and concerns and some rationale for his actions together with some consideration and thought for the rest of the family and their future," Cutler said. "There is some suggestion that Richard was abusive to Sarah during the relationship, but there is no complete consistency with different sides of the family having different views."

"It does seem apparent that Sarah and Richard began to grow apart and this led to Sarah developing a new set of friends. From this friendship base, she began an extra martial affair. The arrival of an anonymous letter informing Richard of this affair appears to be the catalyst for the rapid deterioration of the relationship and Sarah moving out of the family home soon afterwards.

One of the children, Tommy Pitkin, who is aged in his 20s, contacted the police when he found the note. Tommy told an inquest on 18 December that his father was "laughing and messing around as normal" on the day of the murder.

Richard had been googling how to murder himself and his wife. "We strongly believe that Richard planned these deaths and it was not a spontaneous act on the morning," Cutler said.