Sarah Barrass and Brandon Machin, who was her half-brother, had six children together during an incestuous relationship.
But on Friday, May 24, 2019 the evil couple killed two of their sons – Tristan Barrass, 13 and his older brother Blake, 14.
They strangled the teenagers before placing bin bags over their heads in their family home on Gregg House Road, Shiregreen.
They also plotted to murder the other four children by poisoning them but their efforts failed.
The couple also attempted to drown one of the youngsters.
The killers were arrested that day and have been in custody ever since.
They were handed life sentences and ordered to serve a minimum of 35 years behind bars that November after admitting the double murder and conspiracy to murder all six children.
Barrass, now 37 and Machin, 41, killed their children over fears they were at risk of being taken into care and that their sordid relationship would be revealed.
Social services had become involved with the family in November 2018, over concerns about Blake’s behaviour and then about Tristan’s in May 2019.
Barrass had planned to kill herself after killing all the children.
The plan was then for Machin to ‘discover’ what had happened and raise the alarm.
Speaking after the killers were jailed, Edmund Hulbert from the Crown Prosecution Service, said: “This was an appalling crime in which two young lives were lost, and a family torn apart, leaving a community in shock.
“Two of the surviving children witnessed their older siblings being attacked and the trauma that all the children have experienced, and will continue to experience, is unimaginable.”
The home where the Blake and Tristan were killed was demolished earlier this year.
Sanctuary Group, which owned the property, said a memorial will be placed there for the boys.
Bosses said the decision to demolish the house was taken ‘to help the local community move forward’.
The surviving members of the family were consulted and supported the demolition.