The last words from Texas teenager Sarah Said were 'Oh my God, I'm dying'. Then the 911 emergency operator heard a barrage of gunshots.

Sarah, 17, and her sister Amina, 18, were found shot 11 times in the back of their father's taxi, abandoned in a hotel parking lot in 2008.

Their father Yaser Abdel Said is wanted by the FBI for their murders.

Now seven years on, a documentary called 'The Price of Honor' which was screened in Washington this week explores the sisters' story and brings to light the subject of honor killings in the US.

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Amina Said, 18, pictured left, and her sister Sarah, 17, pictured right, were killed on New Year's Day in 2008

Amina and Sarah's father Yaser Abdel Said is thought to be responsible for their murders. He disappeared after their deaths and is wanted by the FBI

This week a movie about the girls' story called 'The Price of Honor' (pictured left) was screened in Washington. In it their father Yaser Abdel Said (pictured right) is accused of honor killing

The film tells how the American teenagers were unable to slip free of their Egyptian father's suffocating control, ultimately victims of what filmmakers say is a trend of honor killings that goes unrecognized in the US.

In the documentary Ruth Trotter says: 'Amina always knew that Yaser was going to murder her, it was just a question of when and where.'

Amina was dating Trotter's son, Joseph, when she died, and Sarah also had a boyfriend, though both had tried to keep this from their father.

'She made Joseph promise that he would not harm himself, that when she dies he would live,' Trotter added.

Joesph Trotter, pictured left, was dating Amina. His mom Ruth Trotter, pictured right, says in the documentary that the girls were victims of 'honor killings'

The documentary reveals that when Amina was 15 Yaser took his daughters to Egypt to find husbands.

Trotter said he picked one man who was almost 50 for Amina to marry but she begged and pleaded with her mother to come back home.

Trotter added that Amina and Sarah had nowhere to turn in Texas. No one understood that a teenager saying 'My Dad is going to kill me' is a serious cry for help, not adolescent drama.

Honor violence is a crime without a name in the US. No data is collected on its prevalence, many people think it happens in countries far, far away from the US, experts on gender-based violence said.

Its forms range from domestic violence for defying parental authority or behaving 'too Westernised', to extreme sexual control including female genital mutilation (FGM), forced marriage and ultimately killings to protect the family's reputation in a conservative community.

A recent study by the US Justice Department quoted research that estimates between 23 and 27 honor killings occur each year in the US and there are 1,500 forced marriages. But there are no official statistics.

A separate study by the Population Reference Bureau estimates that 507,000 women and girls in the US are at risk or have already undergone FGM, where her genitalia are partially or totally removed to control sexuality and ensure virginity until marriage, more than twice the number estimated 15 years.

Yaser Abdel Said is wanted by the FBI over the murders of his daughters Amina and Sarah

Another wanted poster for Yaser Abdel Said which was released by the FBI naming him as one of its most wanted

Director of 'The Price of Honor' Xoel Pamos, in an interview with the Daily Beast, said he found honor killings were different from domestic violence, as other family members were often involved in the violence.

'In honor violence, it's a person who has the support of his own family to not only abuse but kill a woman,' Pamos said.

Amina Said, pictured right, and her sister Sarah, left, angered their father when they started dating non-Muslim boys

When Pamos began researching the documentary, which was screened in Washington last week, he said he set out to tell stories from women around the world but the tragedy of Amina and Sarah captivated him.

He said authorities had ignored signs of family turmoil, he said.

Their maternal grandmother recounts in the documentary how she alerted the police when the girls confided that their father was sexually touching them.

But she said Amina and Sarah recanted, urged on by their American mother to keep daddy out of jail.

After their deaths, police did not interview all family members and potential leads turned cold, Pamos and Trotter said.

In producing the movie, Pamos and his co-director, Iranian-born Neena Nejad, hired a team of private investigators.

They uncovered a video showing the father spying on his daughter as she worked in a convenience store and his anger when she smiled at a customer.

They uncovered cellphone records that showed Yaser making multiple calls to family members immediately before and after his daughters' deaths. Then he disappeared.

Director Xoel Pamos, the filmmaker behind 'The Price of Honor'

Irving Police said they followed up on every credible lead but Yaser, 58, remains wanted by the FBI.

James McLelland, Irving Police Department spokesman, said police do not view the case through a cultural lens, and investigated it no differently than any other homicide.

'We are not giving any credence to honor, but approach it as capital murder. Whatever the motivation was, is for him to explain. The end result is the same,' McLelland said.

Pamos said Amina and Sarah's story is a horrific tale about what happens when honor violence is ignored. 'We need to be aware this a real issue in the US,' he said.

'We need more men, more Muslim men to fight,' said Pamos.

'To sign up and protest that you cannot move to the United States and marry a white lady and say to your daughters you cannot date an American guy.'

'You cannot come and violate basic human rights.'