London (CNN) -- A man accused of killing his teenage daughter in England because of her "Westernized" lifestyle denied the murder in court Wednesday.
Iftikhar Ahmed said it was "devastating" to be on trial for murdering his daughter Shafilea, CNN affiliate ITV reported.
He was taking the stand for the first time in a case which has gripped Britain since the 17-year-old disappeared in September 2003.
The court case took a startling turn Monday when Iftikhar's wife Farzana abruptly changed her long-standing story and said she had seen her husband attack their daughter on the night Shafilea died.
Both parents are accused of the murder. One of Shafilea's sisters testified that she saw her parents push Shafilea onto a couch, stuff a bag into her mouth, and hold her down until she suffocated.
Iftikhar and Farzana Ahmed have both pleaded not guilty at their trial in Chester, England.
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.
The teenager's dismembered body was found on a riverbank months after she disappeared. She had been stripped of anything that would identify her, prosecutor Andrew Edis told the jury in May, according to ITV.
Shafilea's sister Alesha testified last month that she saw her parents kill the girl.
She said her parents were angry that Shafilea was wearing a short-sleeved, V-neck top, and no sweater, on the night she was killed.
"Just end it here," Farzana said to Iftikhar, according to their daughter.
They pushed Shafilea down onto a sofa and suffocated her despite her struggles, Alesha testified.
Prosecutor Edis called it "an act of suffocation by both parents acting together."
Alesha Ahmed did not tell police she had seen the killing until 2010, after she was detained by police in connection with a robbery of the family's home, ITV reported.
She has pleaded guilty to robbery. Prosecutors said she had not been offered any sort of deal in exchange for testifying against her parents.
She has testified that both her parents physically abused Shafilea "every day" over the course of five years, and that her mother did it more "because she was at home more."
On Monday, Farzana unexpectedly said she had seen her husband attack Shafilea. She said that she tried to intervene to protect the girl, but that her husband pushed her away and punched her, 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.
Farzana Ahmed testified Monday that only one of their children, Mevish, was present when she saw her husband attacking Shafilea.
The jury was told that Shafilea had been taken to Pakistan for a hastily arranged marriage before her death, and drank bleach when her parents suggested she was staying there when the rest of the family returned to England, ITV reported.
She was hospitalized for three months after the family came home because of the bleach incident, Alesha testified.
Alesha testified in May that her parents were very strict with their daughters, ITV reported.
"Our family was very restricted. It was very different. The Pakistani culture is more restrictive in terms of what you can wear or do," she said.
The trial began in May and is expected to last several more weeks, prosecutors say.
Reliable figures of the number of honor murders around the world are hard to come by, but the United Nations Population Fund has estimated there could be 5,000 per year.
So-called honor murders are a significant enough problem in Britain that the country's Crown Prosecution Service has an expert specializing in cases in which members of a family kill relatives because of behavior that they say shames the family.
The CPS began keeping statistics on honor violence in April 2010 and prosecuted 234 cases in the following year, just over half of which were successful.
There is a perception that the crime is particularly common among Muslims, but one vocal British campaigner says not all honor violence is perpetrated by Muslims.
Jasvinder Sanghera, who was the victim of a forced marriage, is not Muslim; she is Sikh.
"Significant cases are happening within South Asian communities, be it Pakistani, Indian, Sikh, Muslim, Kurdish, Iranian, Middle Eastern communities," she said.
The killings take place in many parts of the world, experts say.
"It's definitely a problem that happens in many different places: the Middle East, Pakistan, Bangladesh and among immigrant communities in North America," said Nadya Khalife, a researcher on women's rights in the Arab world for Human Rights Watch.
Several Arab countries and territories, including Iraq, Kuwait, Syria, Yemen and the Palestinian territories, have laws providing lesser sentences for honor murders than for other murders, Human Rights Watch says.
Egypt and Jordan also have laws that have been interpreted to allow reduced sentences for honor crimes, the group says.
CNN's Atika Shubert contributed to this report.