At the start of their trial at Chester Crown Court, the jury heard Alesha Ahmed witnessed the killing.The prosecution alleges the couple killed their daughter because she was Westernised and refused to obey them.
He said they embarked on a "campaign of domestic violence to force her to conform". Iftikhar Ahmed, 52 and Farzana Ahmed, 49, of Warrington, deny murdering their daughter He said the case had taken a long time to be brought to trial because it was not until August 2010 that a witness to the crime came forward.
"This witness is Alesha Ahmed, Shafilea's younger sister," he said.
The court heard how Alesha had kept quiet for seven years and only told police after she was arrested for taking part in a robbery at her parents' home in Liverpool Road, Warrington.
Mr Edis said Alesha witnessed the killing of her sister by their parents "acting together".
"This evidence was the final piece of the puzzle which the police had been trying to solve for many years."
The court was told that Shafilea had been abused by her parents in the year before her disappearance.
The court heard Shafilea was taken to Pakistan by her family in 2003 in an attempt to force her into a marriage.
Mr Edis said she drank bleach on the trip as her parents tried to bully her into an arranged marriage.
The defendants later claimed Shafilea drank the bleach by mistake, thinking it was mouthwash.
When she was brought back to the UK she was treated at Warrington Hospital where she spoke to a fellow patient called Foisa Aslam.
Ms Aslam later told police that she asked Shafilea why she drank the bleach.
Shafilea replied: "You don't know what they did to me there."
The court heard that Shafilea told Ms Aslam that the Ahmeds had accepted a rishta (or formal offer of marriage) for her.
Mr Edis said: "That was why she said she drank the bleach."
Shafilea disappeared from the family home in Great Sankey, Warrington, in September 2003.
Her body was found by workmen on the banks of the River Kent, near Kendal, six months later.
The trial continues.
What is it with Pakistanis and forced marriages??????
