A man who killed six people in Jersey, including his wife and children, has died in prison in England.
Damian Rzeszowski was sentenced to 30 years after stabbing Izabela Rzeszowska, 30, Kinga, five, and Kacper, two, in August 2011.
He also killed his father-in-law, his wife's friend and her daughter.
"Damian Rzeszowski died in custody at HMP Full Sutton on Saturday 31 March 2018," said a Prison Service spokesperson.
"As with all deaths in custody, there will be an independent investigation by the Prisons and Probation Ombudsman."
Damian Rzeszowski was cleared of murder but found guilty of manslaughter due to diminished responsibility at Jersey's Royal Court in 2012.
Rzeszowski also killed his father-in-law Marek Garstka, 56, his wife's friend Marta De La Haye, 34, and her daughter Julia De La Haye, five, after a summer barbecue at his home in St Helier.
During his trial it was revealed that the killer's marriage had been under strain after his wife confessed to having an affair.
It also heard how he had threatened to kill himself and had been suffering moderate to severe depression, which had caused an onset of psychotic symptoms.
The couple married in Jersey in 2005 and had two children, Kinga and Kacper.
Rzeszowski had worked on building sites as a foreman's assistant.
The States of Jersey Police (SOJP) said it had been notified about his death.
A statement said: "An investigation into his death will be carried out by the UK Police. SOJP will not be issuing any further information."