The stepfather of murdered schoolboy Daniel Pelka has died in prison - six months after the victim's mother was found hanging in her cell.
Mariusz Krezolek was discovered unresponsive in his cell at HMP Full Sutton in Yorkshire on Wednesday morning and pronounced dead shortly after, the Prisons Service confirmed.
The 36-year-old's partner Magdelena Luczak, 29, who was convicted of Daniel's murder alongside him, died at HMP Foston Hall in July last year.
A Prisons Service spokeswoman said: "HMP Full Sutton prisoner Mariusz Krezolek was found unresponsive in his cell at 8.30am on Wednesday 27 January.
"Staff immediately attempted resuscitation but he was pronounced dead shortly after.
"As with all deaths in custody, there will be an investigation by the independent Prisons & Probation Ombudsman."
Luczak was found dead on the eve of what would have been her son's eighth birthday. Her cause of death was recorded as hanging.
Daniel weighed just 1st 9lbs when he died aged four in March 2012. During his final months, he was denied food, forced to perform punishment exercises, confined in a locked box room, poisoned with salt, and subjected to water torture.
A judge at Birmingham Crown Court said that "unimaginable acts of cruelty and brutality" were inflicted on the child.
His mother and Krezolek, both originally from Poland, were convicted of murder and sentenced to at least 30 years in jail in August 2013 after blaming each other for the head injury which ultimately caused Daniel's death.
In December 2014 three Court of Appeal judges threw out challenges by the pair. They rejected a bid by Krezolek to appeal against his murder conviction and dismissed claims from both that their sentences were "excessive".
Luczak's trial heard that Daniel was regularly "imprisoned" for prolonged periods of time in a small, unheated room at his home.
The door to the box room had been adapted by Krezolek so Daniel could not escape or even see out of the keyhole.
Passing sentence in 2013, Mrs Justice Cox said: "It is a particularly grave aggravating feature in this case that, before the fatal blows to his head, Daniel was the victim of chronic and systematic starvation."
The medical evidence, the judge said, showed that Daniel's emaciation was regarded by experts as "unprecedented" in Britain.
The trial also heard that Luczak, despite knowing of Daniel's hunger, gave specific instructions to his teachers that he was not to eat any more food than his small packed lunch because of an eating disorder.