A boy and girl who killed a suspected paedophile "to teach him a lesson" were today facing years behind bars.
They killed Robert Daley, 45, after lawyers dropped a sex abuse case against him.
Mr Daley was found dying of five stab wounds in his Brixton flat on April 23, hours after being told he would not be prosecuted.
The teenagers, who were 14 when they were arrested but are now 15, were found guilty at the Old Bailey on 10-2 majorities.
The boy was found guilty of murder and the girl was found guilty of manslaughter.
The defendants, who cannot be named for legal reasons, were remanded in custody for sentencing next month.
The court heard the girl, her 16-year-old sister and a woman had complained to police that the heavy drinking crack user had abused them.
Only the 16-year-old had been willing to proceed with her allegations.
Soon after receiving a call from police telling him lawyers considered there was a lack of evidence, Mr Daley rang the older girl.
She texted him back telling him to stay away from her and calling him "a pervert".
She wrote: "Stop calling and texting me. I really don't want anything to do with you. You are a perverted man."
The court heard she rang her sister and the boy - the father of the baby she was expecting.
Soon after the 14-year-olds arrived at his home a struggle broke out in the kitchen and he was fatally injured when two knife wounds punctured his heart.
The teenagers denied the charges and told the jury that Mr Daley grabbed the girl round her throat and was trying to indecently assault her.
They said the boy started jabbing him with a knife to try to free the girl as she struggled with 6ft 1in Mr Daley.
The girl told the court she had been indecently assaulted by Mr Daley twice when she was 12.
She wiped away tears and took a sip of water before adding: "He touched me."
Her sister had phoned her on the day Mr Daley died to say he had telephoned and was "talking shit".
The boy told the court: "I saw him pinning her to the worktop. He had his left hand on her throat and his right hand was trying to touch her.
"I told him to stop, screaming at him. He was not paying any attention."
Jonathan Rees, QC, prosecuting, told the jury that the evidence suggested Mr Daley was something of a "Jekyll and Hyde character".
But he warned that "this is not a vigilante society". People were not allowed to take the law into their own hands.
"He is not here to answer allegations which were not proceeded with," said Mr Rees.
"The question you have to deal with is not whether he deserved what he got but whether he was murdered.
"We maintain that following the telephone call, the defendants set out to teach him a lesson using violence.
"Robert Daley was subjected to an unprovoked knife attack in his kitchen. There was no sexual assault or grabbing round the neck."
The victim's mother, Inez Marks, said in a statement to the court: "It feels like I have been stabbed in the heart. I don't think I will ever get over it."
A CPS spokesman said later that it had considered all the evidence in the sex abuse allegations before deciding not to go ahead.
She added: "The young female defendant in this case failed to assist police in that investigation and due to this and other conflicting evidence, the CPS was not satisfied that there was a realistic prospect of conviction."
Detective Chief Inspector David Manning said: "This was a complex case and provided challenges to myself and my team in untangling a number of complex relationships."Reuse content