CHICAGO (AP) _ Police are investigating whether a woman deliberately drove her car into Lake Michigan in a wreck that killed her and two of her children.

The car veered off Lake Shore Drive, went slowly down some steps and paused for a moment before it suddenly accelerated and went into a downtown harbor Monday night, police and witnesses said.

Two police officers went into the murky, 59-degree water to try to rescue the victims. The officers had to be treated for exposure.

Police divers had to break a window to pull out the victims: Shirley Combest, 33, a long-distance operator for Sprint; her daughter, Shaniqua, 8; and her son John, 6. Ms. Combest had a teen-age son who was not in the car.

Ms. Combest had a history of depression and had been under a doctor's care a few months ago, said her mother, Ruthie Mae Combest. She said her daughter also was grieving over the death of an older sister in a car accident last month.

``She was taking it awful hard,'' the mother said.