Jake Sheehan (left) and David Philip had both denied murder
Two teenagers face life sentences after being convicted of murdering a girl and her grandmother in a fire in east London as revenge for an unpaid debt.
Jake Sheehan, 19, of Bethnal Green, and David Philip, an 18-year-old from Bow, had denied the charges but were found guilty by a jury at the Old Bailey.
Shannon Vickers, 17, and Pauline Adams, 57, were killed last February.
The home they shared, on the fifth floor of Malmesbury House in Cyprus Street, Bethnal Green, was set alight.
"Sheehan and Philip had been involved in a long-running dispute with Mrs Adams's grandson over the debt," said Det Insp Larry Smith of the Metropolitan Police.
"The grandson lived with Mrs Adams and Shannon," he added.
Sheehan and Philip told the grandson they would burn his house down, the court heard.
They carried out their threat by pouring petrol through the flat's letter box and igniting it.
"Pauline Adams and Shannon Vickers would have been asleep when the fire was set," said prosecution QC Simon Denison.
"They both woke up. Pauline went to Shannon's bedroom.
"Shannon was heard screaming for just a few seconds but she was not heard again.
The victims' bodies were found in a rear bedroom in the fifth floor flat
"They were both overcome by the smoke and the fumes and they died together, lying side by side - two completely innocent people killed over a £15 debt and not losing face."
The actions of Sheehan and Philip displayed a "callous disregard for life" in "taking the lives of a beloved grandmother and her granddaughter", Det Insp Smith said.
The victims suffered from smoke inhalation which proved fatal, post-mortem tests found. Their pet cat and dog also died.
Det Insp Smith paid tribute to the family, who he said had "shown great dignity and bravery throughout this trial".
"I know the evidence they have heard has been very difficult.
"I hope today's conviction can go some way in assisting them as they try to move forward with their lives," he added.
Sheehan and Philip were remanded in custody and are due to be sentenced on Monday.