The sister of honour killing victim Shafilea Ahmed was spared jail when she was given a 12-month suspended sentence for organising a robbery at her parents' house.
Alesha Ahmed's arrest ultimately led to the conviction of her parents, Iftikhar and Farzana, for murdering their eldest daughter.
While being interviewed about the robbery, Alesha, now 24, revealed to detectives for the first time that she and her siblings witnessed Shafilea's murder seven years earlier.
Shafilea, 17, vanished in August 2003 and her decomposed remains were discovered in Cumbria in February 2004 but it was Alesha's statement to police that provided enough evidence to charge the parents, leading to their convictions this year.
She was sentenced to a 12-month prison sentence, suspended for two years, at Southwark Crown Court, in London, after previously pleading guilty to robbery. She helped organise the crime at her parents' home in Warrington in August 2010.
Sentencing the 24-year-old, who is in a witness protection scheme, Mr Justice Irwin said: "In my view, this is a case for mercy. I bear in mind all of the extraordinary circumstances I have outlined, in particular the truly appalling nature of what you had to witness, the impact this has had on you, and what you went through to be a witness.
"I bear in mind that, despite your undoubted intelligence and despite the help you may be given, your future life will be overshadowed by all that has happened, and it may be a long time before you achieve peace of mind and anything like normality."
He said robbery in the home was a very serious crime and she would have realised it would be a terrifying experience and said the normal sentence for an offence of this kind would be a significant jail sentence, even for someone of good character who pleaded guilty.
But he said that although Ahmed's role in the robbery was "crucial", there was a "degree of unreality" about how she behaved. He said she had been in witness protection for more than two years, adding: "This can properly be compared to house arrest, and I accept it had an especially intense effect on you, since you were psychologically vulnerable, you were in a state of conflict with your family, isolated and away from friends and any ordinary support."
He said Ahmed was not trying to bargain for a lower sentence in giving evidence and had asked to be sentenced before her parents' trial. Handing her a 12-month prison term, suspended for two years, the judge said she would be supervised by the probation service and will also have to undergo continuing mental health treatment, adding: "I am confident you will not re-offend."