A man ordered to serve the rest of his life in prison for torturing and murdering his former partner and two-year-old daughter has died.
David Oakes, 50, was jailed last year after Chelmsford Crown Court heard he went to Christine Chambers's house in Braintree, Essex, where he subjected her to "degrading assaults" before blasting her and their daughter Shania with a shotgun.
The Ministry of Justice confirmed that Oakes had died from natural causes after being taken to hospital.
A Prison Service spokesman said: "HMP Frankland prisoner David Robert Oakes died at hospital on Monday. He is presumed to have died from natural causes.
"As with all deaths in custody, the Independent Prisons and Probation Ombudsman will conduct an investigation."
Oakes had denied two counts of murder but was found guilty after nine hours of jury deliberations at his trial in May.
Mr Justice Fulford ordered Oakes to serve a whole life sentence, making him one of a limited group of inmates who would never be released from prison.
Describing Oakes, he said: "A bullying and controlling man, who had frequently inflicted violence on Miss Chambers during the six years of their relationship, he killed his ex-partner and their young daughter simply because he knew she could not bear to be with him and wished to start a new life."
The trial heard Oakes forced Miss Chambers to cut off her own hair, after arriving at the house with the shotgun, a drill and an axe. Oakes did not appear in court to be sentenced, after prison guards raised concerns he would harm himself.
In November, the Court of Appeal refused to quash the whole-life order imposed on the killer. He was one of several inmates who argued such orders were incompatible with Article 3 of the European Convention of Human Rights, which prohibits torture and inhuman or degrading treatment and punishment.