Updated

As the family of two teenage Texas girls allegedly shot by their father and left to die in his taxi prepared to bury them, their brother issued a plea to his father.

"I just hope he turns himself in because, you know, he messed up the whole family," Islam Said, 19, told MyFOXDFW.com after his sisters were found dead Tuesday night.

Said said his father, Yaser Abdel Said, 50, of Lewisville, Texas, was having a very hard time when his daughters, Sarah Yaser Said, 17, and Amina Yaser Said, 18, started dating.

Connie Moggio, the girls' aunt, said there had been turbulence in the Said household for a while.

She said her sister married Yaser Abdel Said at the age of 15 and was pregnant shortly after, adding she had tried to leave her husband many times over the years, most recently, on Christmas Eve.

"A few days before she called me at my job and told me she was leaving because he had threatened the girls because they were dating," Moggio told MyFOXDFW.com.

Click here to watch the full interview from MyFOXDFW.com.

Police said they do not have a motive for the shootings but believe a domestic issue may have led to the deaths.

Their funeral was to be held at noon on Saturday in Dallas.

Friends and Lewisville High School classmates of the Said girls posted photos and comments in a tribute to the sisters set up on the social networking site Facebook.com called "Rest in Peace, Sarah & Amina."

Click here to see photos.

The page's creator, friend Jenny Lee, encouraged people to document their memories of Amina and Sarah Said.

"We love you so much, and miss you already," she wrote.

Information about memorial services and developments in the case are also included on the Facebook page.

"How could anyone do this to two beautiful, bright young ladies?" one visitor wrote.

A local Austin imam condemned the murders on the tribute page, and in another note, a girl identifying herself as a former classmate of Sarah's wrote that Yaser Abdel Said abruptly moved his family to Lewisville a few years ago because he was unhappy about a boy his older daughter, Amina, had been dating.

Loved ones gathered Thursday night for a vigil to remember the sisters. The girls' mother, who has been in hiding since the shootings, attended.

The victims' brother made a statement at the vigil that the deaths have nothing to do with religion.

David Tull, a spokesman for the Irving Police Department, told FOX News that there is not a specific motive but police are aware of domestic issues within the family.

Tull would not comment directly on shootings being tied to reports about the girls' wearing Western clothes and disobeying their father's wishes.

Click here to watch a video report by MyFOXdfw.com.

Brigitte Gabriel, author of "Because They Hate: A Survivor of Islamic Terror Warns America," said the shootings point to an "honor killing."

"This crime has honor killing written all over it," Gabriel said. "The father was insulted and ashamed of how his daughters were behaving."

The daughters were bringing shame to Islam and the father took it upon himself to respond, Gabriel said.

"The father probably was seeing that this is going to bring shame on the family and he needed to eliminate that shame," Gabriel said.

The girls' brother denies this claim, saying the Islamic religion is peaceful.

One of the teens called 911 on a cell phone about 7:30 p.m. Tuesday and said she was shot, but she couldn't tell police where she was, police said.

Officers were dispatched to the area, which turned out to be about half a mile from the taxi, but did not find anyone, according to reports. Police found the taxi with the bodies inside an hour later after a witness called and reported a suspicious vehicle in a hotel parking lot, police said.

Authorities announced a $10,000 reward Friday for information leading to the arrest and indictment of Yaser Abdel Said.

Yaser Abdel Said is about 6-foot-2, weighing about 180 pounds and has black hair and brown eyes. He last was seen wearing a black turtleneck shirt or sweater, a brown coat and tan pants. He is believed to be armed with a handgun, police said.