A "sadistic bully" who murdered his own two-year-old daughter and her mother has died in jail.
David Oakes, 50, was found dead at HMP Frankland prison where he was serving life for the deaths of former partner Christine Chambers, 38, and daughter Shania.
A prison service spokesman said: "HMP Frankland prisoner David Robert Oakes died in 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 killed Chambers and their daughter after arriving at his former partner's home in Braintree, Essex armed with a shotgun, drill and axe in 2011.
He shot them both with the powerful firearm after Chambers told him she would never take him back. Before pulling the trigger, Oakes inflicted "degrading assaults" and "sadistic" torture on Chambers.
The gunman had planned to kill himself after carrying out the murders, but failed to do so.
The nature of the crimes led Mr Justice Fulford to hand down a full life sentence to Oakes, making him one of only a handful of UK prisoners with no prospect of release.
Former friend Ian Flitt said Oakes' death was for the best. "It is welcome news and the end to a sad saga. His death is probably the best thing for everybody concerned, including him."
At his trial for the murders at Chelmsford Crown Court, the judge said Oakes "planned the deaths in elaborate detail." He made Chambers beg for her life and say she loved him while torturing her.
Judge Fulford said: "Shania would have witnessed her mother's gravely injured state and heard her cries for help. She would have seen the appalling injuries to her mother.
"That little girl must have been terrified. He then put the shotgun against her head and pulled the trigger.
"No decent, civilised human being could ever describe that as being the result of love."
Oakes was described as "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," said the judge.
Chambers' sister Jeanette said Essex Police had failed to take several reports of domestic abuse seriously during her relationship with Oakes.
After being jailed, Oakes mounted appeals against his full-life sentence on the grounds it was incompatible with the Human Rights Act. He was also identified as being at risk of self harm.