The North Texas Crime Commission has added $10,000 to the reward money already being offered in the case of two sisters who authorities believe were killed by their father on New Year's Day.

Rewards in the case now total $20,000.

Yaser Said, an Egyptian-born cab driver, has been missing since the shooting deaths of his two daughters, 17-year-old Sarah and 18-year-old Amina. The sisters, who were honor students and athletes at Lewisville High School, were found slain in a cab their father had borrowed at an Irving hotel. Police have said they have no leads about Mr. Said's whereabouts.

"I just think that money talks, and we've done everything else we know to do" to find him, said Gail Gartrell, the sisters' great-aunt. "I just think that getting more money up on his head is a good thing."

The crime commission's reward is for information leading to the arrest and conviction in the killings. Schepps Dairy already was offering a $10,000 reward for an arrest and indictment in the case.

Anyone with information on Mr. Said's whereabouts can call Crime Stoppers at 1-877-373-TIPS or go to www.ntcc.crimestoppersweb .com.

The crime commission also is creating a special fund to raise more reward money. Donations can be made out to the North Texas Crime Commission Said Fund and mailed to the North Texas Crime Commission, 1601 Elm St., Suite 2350, Dallas, TX 75201-4728.