Husband implicated in 'honor murder'

• Shafilea Ahmed's parents are accused of killing the British teen in a "honor murder"
• They deny the killing, but on Monday the mother says she saw her husband attack the girl
• Shafilea's sister testified last month that she saw her parents stuff a plastic bag in her mouth
• The prosecution charges the parents were ashamed of Shafilea's "Western" lifestyle

London (CNN) -- In a trial that has been front-page news in Britain, a woman accused with her husband of killing their daughter in an alleged "honor murder" abruptly changed her defense this week implicating her husband in the teen's death.

Ifitkar Ahmed and his wife Farzana are on trial in Chester, England, accused of killing Shafilea, 17, in September 2003. They have pleaded not guilty.

Newspapers, television and radio have all been reporting on the prosecution case that Shafilea's parents killed her because they felt her "western" lifestyle brought shame on the family.

On Monday, Farzana said she had seen her husband attack Shafilea. She said she tried to intervene to protect the girl, but that her husband pushed her away and punched her, CNN affiliate ITV reported.

"Extremely scared," she fled the room and stayed in a bedroom with other children until she heard a car leaving 20 minutes later.

When her husband returned alone, she asked where their daughter was.

"If you care for your dear life and that of your children, don't ever ask me this question again," he told her, ITV reported.

Shafilea's sister testified last month that she saw her parents kill Shafilea by stuffing a plastic bag into her mouth.

Alesha Ahmed, Shafilea's younger sister, did not tell police she had seen the killing until 2010, ITV reported.

Farzana Ahmed testified Monday that only one of their children, Mevish, was present when she saw her husband attacking Shafilea.