DALLAS (AP) The driver involved in a fatal bus crash earlier this month failed to maintain his lane along a North Texas highway before the bus careened off the roadway and struck a concrete barrier, authorities said Monday.

A preliminary investigation found no defect with the Cardinal Coach Line bus, and instead cited an error by driver Loyd Rieve, 65, said Texas Department of Public Safety Sgt. Lonny Haschel.

The bus was taking senior citizens to a casino in Oklahoma when it struck the barrier in Irving and toppled over April 11, prompting a large emergency response.

Two people were killed and more than 40 hurt in the immediate aftermath. Haschel said a third passenger died Sunday from injuries she suffered.

Rieve was not immediately available for comment. A phone message left with Cardinal Coach Line, based in Mansfield, was not returned.

Court records show Rieve was driving for another company in 1998 when he struck and killed a man who was trying to render aid at an accident scene on a highway near Dallas. A Dallas County grand jury declined to indict Rieve on a charge of negligent homicide stemming from the collision, but Rieve and his employer still faced two lawsuits claiming they were negligent.

One lawsuit, filed by the family of the man who was killed, resulted in a jury finding Central West Motor Stages Inc. of Grand Prairie was negligent for employing Rieve. However, the jury awarded no damages, deciding the Samaritan, 22-year-old Chad Rosell of Detroit Lakes, Minn., was largely at fault.

Rieve's wife, Gail Rieve, told The Associated Press earlier this month the bus struck Rosell because he jumped onto the road and the vehicle's brakes were faulty.

"Loyd did everything he could to save those people on the bus and that young man," she said.

Alice Stanley, 82, Paula Hahn, 69, and Sue Taylor, 81, were killed in the latest bus crash. The other 44 passengers sustained various injuries. Taylor, known as "Casino Sue," organized trips to casinos all over Oklahoma and Mississippi, complete with treats for riders and prizes for the biggest loser.