The parents of six children who died after a house fire in Derby, Mick and Mairead Philpott, have been convicted of their manslaughter together with their friend, Paul Mosley.
Mick Philpott and Paul Mosley were found guilty by unanimous verdicts, while Mairead Philpott was convicted by a majority, at Nottingham Crown Court.
Philpott hoped the fire would frame his ex-mistress, Lisa Willis, for the attack so he could win custody of his children.
A senior police officer said it was the most tragic case he had worked on.
Derbyshire Assistant Chief Constable Steve Cotterill said: "There are six little kids there that have not got the chance to grow up.
"Personally I have found it very upsetting. I have become extremely angry at the needless loss of life."
Five of the children died on the morning of the fire in Victory Road, and the sixth died three days later. Jade Philpott, 10, John, nine, Jack, eight, Jesse, six, and Jayden, five, died on the morning of the fire on 11 May 2012.
Mrs Philpott's son from a previous relationship, 13-year-old Duwayne, died later in hospital.
Jurors heard that Philpott had been violent and controlling towards his former live-in mistress, Lisa Willis.
But the jurors were not told that Philpott had been jailed in 1978 for attempting to murder a 17-year-old ex-girlfriend.
He stabbed her 13 times as she lay sleeping after she ended their relationship, and also attacked her mother when she intervened. The three defendants were found guilty after less than eight hours of deliberation.
The judge, Mrs Justice Thirlwall, said the defendants would be sentenced on Wednesday.
As the court heard the guilty verdicts, Mairead Philpott looked down at the floor and appeared upset while holding a tissue in her hands.
Before leaving the dock, Mick Philpott was heard to say: "It's not over yet."
In a statement read outside the court, Mick Philpott's sister Dawn Bestwick said: "Our presence in court was to find out the truth and following today's verdict we believe justice has been done.
"This past year has been a very difficult time for our family as we have had to come to terms with what Mick and Mairead and Paul Mosley have done. We can now move on and our six angels can rest in peace."
A statement read on behalf of the Duffy family, the family of Mairead Philpott, said: "Duwayne, Jade, John, Jack, Jesse and Jayden were taken away in the cruellest way imaginable by the very people that were supposed to love and protect them.
"We, Mairead's family, cannot describe the pain we feel. Today justice has been done and we are happy with the verdict."
Update April 4
Mick Philpott has been sentenced to life in prison for the manslaughter of the six children. Mairead Philpott and Paul Mosley were both jailed for 17 years.