Dead UK teen's sister: Our parents murdered her over Westernized lifestyle PA via AP, file Shafilea Ahmed was allegedly murdered by her parents. LONDON -- A young woman has told a court in England that as a child she witnessed her 17-year-old sister being murdered by their parents after a months-long quarrel about the teen's Westernized lifestyle. Alesha Ahmed, 22, who is in a witness protection program, told a court in Chester, England, that she watched as her parents suffocated Shafilea Ahmed at their family home in Warrington in 2003, ITV News reported. Prosecutor Andrew Edis told the court Tuesday that Iftikhar Ahmed, 52, and Farzana Ahmed, 49, put their hands over their daughter's face "to close her airways so she could not breathe" and that "she had a bag forced into her mouth." Read more on this story from ITV News 'Dishonored the family' Edis said that they murdered their daughter -- after "having spent the best part of 12 months trying to really crush her" - because she had "dishonored the family, bringing shame on them." The family is of Pakistani origin. Alesha Ahmed told the court Tuesday that her parents would often argue with their older daughter over the clothes she wore, her friends and who she was speaking to on the phone. Shafilea was leading a life she thought our parents would not approve of ... There would be physical abuse directed at Shafilea. It was both of them. My mum more because she was at home more," she said, according to ITV News. There was an incident in the kitchen, she had her hair in a plait and my parents had a knife to scare her. They passed the knife between them. I was in the kitchen then ran off," she added. They were just hitting her. It was frantic and out of control and she just sat there taking it. The knife was used to scare her. After I saw she had marks on her neck. Alesha Ahmed did not tell police that she had witnessed her sister's death until 2010 after she was arrested over a robbery at her parents" house, ITV News reported. She is still to be sentenced over that offense, but Edis said she had not been given "any promises or indeed any inducement prior to when she first made these allegations." Read more stories from Britain's ITV News Edis said her claim was either the truth or "a wicked lie made up to help herself." The court heard that police had secretly put a listening device into the Ahmeds" home in November 2003 when Shafilea Ahmed was still considered as a missing person. Three Canadians jailed for life for 'honor killings' Farzana Ahmed was heard telling one of her other children, "if the slightest thing comes out of your mouth, we will be stuck in real trouble. Remember that," ITV News reported. 'Honor killings' require tougher laws, Iraqi women say The Guardian newspaper said that Iftikhar Ahmed was heard saying, "By getting the support of newspapers, you can get away with murder." Honor killings: Moms accused of slaying 2 brides Edis said the father was also heard saying "What are they going to find in the car?," while his wife said "Even if they find saliva in the car, it's not as if she didn't sit in the car." The dead girl's body was found beside the River Kent in Cumbria, England, in February 2004.