It's been one week since two teen sisters were found shot to death inside a cab outside a Texas hotel, and their father, who police say is the sole suspect in the New Year's Day killings, remains at large.
Authorities tell ABC News that the investigation so far has produced few solid leads as to Yaser Abdel Said's whereabouts, and they fear he may have fled the country, perhaps even to his native Egypt. Police say they believe Said, a taxi driver, was driving the cab that evening.
"As far as I know, there haven't been any sightings of him," Officer David Tull, spokesman for the Irving Police Department, told ABC News about the 50-year-old Said. "He's had a week now, so he could be pretty much anywhere."
The sisters, Sarah Yaser Said, 17, and Amina Yaser Said, 18, were buried Saturday. Their mother, Patricia Said, broke her silence about the case at a candlelight vigil for her daughters Thursday. She reportedly told a crowd of mourners that the girls — especially their vibrant smiles — would be missed.
Before the funeral Saturday, Patricia Said made a public appeal for her husband to turn himself in. "We will not quit until we find you," she said. "If it's the last thing I do, I promise, I will find you."
The couple's son, 19-year-old Islam Said, also spoke to the media, saying that his father had "messed everything up" by murdering his sisters, who have been described as popular students at Lewisville High School and inseparable siblings.
At the vigil Thursday, Islam Said also tried to squash rumors that the family's Muslim heritage may have had something to do with his sisters' murders.
"Religion has nothing to do with this and it was very wrong," Islam Said said, according to the Star-Telegram in Texas. "Islam is not a bad religion."
Still, the case has generated significant speculation — including by some friends of the girls — that the father's motive may have been some sort of an "honor killing" in the Muslim tradition. Specifically, the reported Westernized behavior of the teens, including the boys they dated, may have brought shame to a father said to be strict and religious, prompting the killings.
While acknowledging that the idea of an "honor killing" is being talked about widely in the Texas community, Tull said the Irving Police Department would not comment on the speculation and still have not confirmed a motive beyond some type of existing domestic discord.
"There's a lot of facets to this case," Tull said when asked about the "honor killing" motive. "We're very well aware of the various domestic issues and the dynamics of this family."
On a Facebook page devoted to the teens' memories, many friends and strangers have offered prayers and memories of two classmates described as full of life and typical of American high school students, some even offered theories on the murders.
Group member Morgan Brooke Lee wrote that she was formerly a classmate with Sarah Yaser Said, but that the Saids abruptly moved to Lewisville. "I found out later from Sarah on MySpace it was because [Yaser Abdel Said] had found out about a boy Amina was dating," Lee wrote in a post.
A Texas imam, who identified himself as Mohamed-Umer Esmail, came out in the Facebook group to condemn the crime and ask Allah to grant the sisters a place in "paradise." He also requested that the community recognize the peacefulness of the Muslim faith, amid speculation about the crime.
Zohair Zaidi, identified as a friend of Sarah's, told the Dallas Morning-News that Yaser Abdel Said had recently threatened Amina after discovering the teen had a boyfriend.
"He told Sarah, 'I'm going to put a bullet through Amina's head, and you better get used to her because she's not going to be around much longer,'" Zaidi told the paper, citing a conversation she had with the younger of the two sisters.
Police say they originally received a 911 call, from one of the two sisters New Year's Day at 7:33 p.m. The young woman told the dispatcher she had been shot, but could not tell police where she was or who had shot her.
An hour passed between the first 911 call and a subsequent call to police made by a staff member at the Omni Mandalay Hotel in Irving reporting that two women were passed out in a cab at the hotel's taxi queue.
Authorities, who were in the area after tracking the cell phone signal from the 911 call, arrived to find the sisters dead inside a cab that Yaser Abdel Said had been driving. Each had been shot multiple times and their father was missing.
"We don't know how he left the scene," Tull said, adding that it may have been by foot or by car. A SWAT team entered the Said house the following day, but failed to find the suspect.
Authorities have obtained an arrest warrant for Said on two capital murder charges and are now working with state and federal investigators to find the wanted man. A $10,000 reward has been offered for information leading to Said's indictment.
Said is described as 6 feet 2 inches tall, with black hair and brown eyes. Police believe Said may be carrying a handgun.
In December, religious tension played a role in the murder of Aqsa Parvez, a 16-year-old who police say was strangled by her father, Muhammad Parvez, also a cabdriver. Part of that dispute reportedly had to do with the teen's resistance to wearing a traditional "hijab" or a head scarf.