A couple were killed in their home as their two children were asleep upstairs, police have said.
Jennifer and Stephen Chapple were found seriously injured at the house in Dragon Rise, Norton Fitzwarren, Somerset, on Sunday. They died at the scene.
Their children, aged five and six, are being looked after by family members.
Two men, aged 34 and 67, were arrested on suspicion of murder. The older man has been released under investigation.
Magistrates granted an extension to the custody time limit in relation to the younger man.
A post-mortem examination confirmed Mrs Chapple died from multiple stab wounds.
Investigations into Mr Chapple’s cause of death are ongoing.
Det Insp Neil Meade, of Avon and Somerset Police, said: “What happened to Stephen and Jennifer is utterly heart-breaking and I can’t begin to imagine the impact their deaths will have on their two children.
“This is a tragic incident which has shocked the community.”
Officers were called to the property in the village near Taunton at about 21:45 GMT. Cordons remain at two properties on the housing estate as officers continue to examine them.
Tributes have poured in to the couple since news of their deaths emerged.
Mr Chapple, 36, taught computing at the nearby West Somerset College. Head teacher Gregg Mockridge said he will be “sadly missed”.
“Steve was a fantastic colleague at West Somerset College, a brilliant teacher that cared deeply about the students in his care,” he said.
Mrs Chapple, 33, worked in the coffee shop at a garden centre in the village, where staff said they were “devastated” at the loss of their “much-loved friend”.
Taunton MP Rebecca Pow said it was “absolutely tragic and shocking” to hear the news.
She said: “It’s a very close knit community so it is really devastating news. I’m sure it would have shaken them to their foundations.”
Avon and Somerset Police would not comment on social media reports that there had been an ongoing dispute about parking on the estate.
But due to prior contact with the couple, the force has referred itself to the Independent Office for Police Conduct (IOPC).