Jackie Frost, driver of tanker truck

Investigators are still trying to determine exactly what caused 64-year-old Jackie Frost's truck to go out of control.

911 tapes from Tuesday's crash reveal a desperate scene...just moments after a tanker truck fell from the Harbor Tunnel Thruway exit on to Interstate 95 killing four people.

Police have revealed the name of the driver of the tanker trunk. Officials say Jackie Frost, a 64-year-old truck driver was from Carroll County, Maryland.

On Thursday Police also identified a second person killed in Tuesday's crash. Maurice Durschlag, 62, of Glen Burnie, Md., was the driver of a pick-up truck involved in the fatal wreck.

Investigators continue to work to indentify two other motorists who died as a result of the accident.

Meanwhile, the wife of the tanker truck driver says she last heard from her husband less than two hours before the accident.

Geri Frost of Finksburg says her husband, Jackie, called to say he had locked his keys in the tanker truck. But he was soon on the road again.

Frost heard about the accident soon after it happened, and began calling her husband's cell phone. It rang and rang, but no one answered. By Tuesday evening, her fears got the best of her.

Jackie Frost leaves behind nine children, ranging in age from 39 to 3. The older four are from a previous marriage.

Frost drove a gasoline tanker for Petro-Chemical Transport, a Texas company. Petro-Chemical says his ten-year record with the company was "exemplary."

Funeral arrangements are pending. Investigators are still trying to determine exactly what caused Frost's truck to go out of control.

To view 9 News' Doug Buchanan's interview with Geri Frost click "Doug Buchanan Reporting," and click "911 Tapes" to learn more about what witnesses saw moments after the accident.

The Associated Press contributed to this report.