A father who strangled his wife and their two young children and was then tasered after holding a knife to his own throat has been jailed for life.

Saju Chelavalel was ordered to serve a minimum term of 40 years after a judge was told the 52-year-old killed NHS nurse Anju Asok while he was drunk last December, in the mistaken belief that she had been unfaithful to him.

Northampton Crown Court was told Chelavalel had more than four hours “to reflect on whether to kill his children” before using a dressing gown cord to kill six-year-old son Jeeva Saju and their daughter Janvi Saju, aged four.

Saju Chelavalel court caseSaju Chelavalel must serve at least 40 years (Northamptonshire Police/PA)

Chelavalel, originally from Kerala in India, sobbed in the dock with his head bowed on Monday as an audio recording was played to the court on which his wife could be heard coughing and his children could be heard talking.

The court was told the recording also captured the sound of a blender being used to make a “toxic” mixture of chocolate and pills intended to send the children to sleep.

Body worn video footage released by Northamptonshire Police after the hearing showed the killer urging police to shoot him at his home in Kettering, where he also left instructions for his own and his family’s bodies to be cremated in India.

Deaths of woman and two children in KetteringA forensic officer at the scene in Kettering last December (Matthew Cooper/PA)

The footage, filmed after officers broke the glass in a patio door to gain access to the ground-floor flat in Petherton Court, shows them issuing repeated warnings for Chelavalel to drop a knife before his arrest.

Ms Asok, aged 35, worked as a nurse at Kettering General Hospital.

Her body was found on the floor of a bedroom at the flat, while the children’s bodies were found next to each other on a double bed in a different room.

Passing sentence, High Court judge Mr Justice Pepperall told Chelavalel his actions had been brutal and “extraordinarily selfish”.

The judge said both child victims would have been “terrified and deeply traumatised” after hearing their mother’s murder.

Both children could have been brought up by other relatives, the judge told Chelavalel, who he said had killed his wife in a “fit of rage” after a minor argument.

The judge said: “Fuelled by alcohol, wallowing in self-pity, engulfed in your resentment at your wife’s perceived infidelity, you instead chose to snuff out their young and precious lives.”

Chelavalel showed no emotion as the judge added: “Even if you had been right in your suspicions, let me make clear that nothing could possibly justify violence, let alone the brutal murders of your family.

“I should make plain that the police did indeed investigate your claim (of an affair) and found no evidence whatsoever that your wife was involved with another man.

Saju Chelavalel court caseSaju Chelavalel seen on police body cam as he was restrained (Northamptonshire Police/PA)

“Not only was her supposed infidelity a figment of your imagination but the police investigation revealed your hypocrisy in that it was you, and not your wife, who had been searching dating websites in the days leading up to these offences.

“Your attack upon your wife was recorded. While you were squeezing the life out of your wife, your young children can be heard crying in the background for their mummy.

“Having listened to that harrowing recording, I cannot be sure that they were eye-witnesses to their mother’s murder but it is clear that they heard what was going on and knew that she was being hurt by you.”

The judge said the evidence showed that within minutes of murdering his wife at about 10pm on December 14, Chelavalel decided his children must also die.

The judge continued: “No psychiatric evidence is put before me to explain any disordered thinking that led you to that extraordinarily selfish and callous conclusion.

Deaths of woman and two children in KetteringFlowers left near the scene (Matthew Cooper/PA)

“At some point after 2.30am, you then strangled both children.”

Speaking to the media outside the court building, Detective Inspector Simon Barnes said the murdered children went to Kettering Park Infant Academy.

He said: “The staff at the school described the children as kind, caring, gentle, playful, polite and smiley. They are much missed.

“How do you explain to children as young as four that the friends they were playing with only days before are no longer with us? You shouldn’t have to. No one should.

“As an adult, detective and father, I cannot comprehend how Saju Chelavalel could do this and don’t think I ever will.

“There is no amount of time behind bars that will ever be enough for what he did. His primary role as a husband and a father was to protect his family from harm.”