The sister of murdered teenager Shafelia Ahmed finally told police she witnessed what happened because she "just had to let it out", a court has heard.
Speaking from behind a curtain at the trial of her parents, Alesha Ahmed told the jury "it had haunted me for a long time about what happened to my sister".
On Wednesday, Ms Ahmed sobbed in court as she described how her mother and father murdered the 17-year-old.
She told Chester Crown Court she saw them suffocate Shafilea at the family home in Warrington in 2003 following years of rows over her sister's "Westernised" lifestyle.
Iftikhar and Farzana Ahmed both deny murdering their daughter.
Asked by Andrew Edis QC why she kept silent about what she had seen until 2010, Ms Ahmed said: "I think it wasn't until I went to university that I saw how wrong the family life is, because when you get used to something it becomes normal.
"That's when I saw it wasn't normal and I knew what happened to my sister was wrong. Because it's your own parents you don't see how bad it is because you still love them."
Ms Ahmed, who is now 23, continued: "I think at university I did really feel like my sister in a way that you want to fit in with everyone else, but you're being forced to live in a different way. That's what made me crack."
She added: "I felt I was going down the same path as my sister Shafilea had gone down, in terms of the pressure of going to Pakistan, in terms of being 21 at the time and supposed to be married."
Ms Ahmed described how her relationship with her parents "completely broke down" when they found out she had refused a proposal of marriage.
She told the court she did not know the man, so she was not happy with it. She added that she had been choosing her own boyfriends.
The court heard she paid for university with loans, but later asked her parents for money, which they refused, and told her to go to Pakistan instead.
Ms Ahmed then told the jury she was responsible for a robbery at her parents' home in August 2010.
Asked why, she said: "I think I just absolutely snapped. It was just hard, either living how they wanted me to live or living on my own. Both were a struggle."
She was asked what she hoped to get out of the robbery.
"I don't really know," she replied. "I wasn't thinking properly."
The court heard that days after her arrest, she told police her parents had killed her sister.
Mr Edis asked: "Before you made that disclosure had any police officer told you it might help you in terms of the trouble you're in, in terms of the robbery?" She replied, "No".
Mr Edis went on: "What was it that made you tell?" She answered that she had "just had enough".
"My mental state wasn't very good, being between the two cultures and trying to please everyone. It just wasn't me anymore. I just had to let it out," she said.
The trial at Chester Crown Court will continue on Monday.