WEST VALLEY CITY, Utah (AP) _ A woman looking for her two daughters and three other children drove around in a car without realizing the girls were locked in the trunk, where they had died of heat stroke.

``This is the horror story inside a horror story,'' West Valley police Lt. Charles Illsley said Sunday. ``The mother's in the car, frantically looking for the children. And they're in the trunk. It's incomprehensible.''

The five children were reported missing after they were playing together Friday afternoon in West Valley, a community just west of Salt Lake City, as temperatures approached 96 degrees. They were found when police officers and one of the mothers popped the trunk on the 1993 Saturn.

They were identified Sunday as sisters Audrey Smith, 2, and Jashea Smith, 6; their cousins, Alisha Richardson, 3, and Ashley Richardson, 6; and a 5-year-old neighborhood friend, McKell Hedden.

The children were being watched by Dixie Smith, the mother of Audrey and Jashea. The Richardson girls were her nieces.

Detectives had not yet determined how the children got into the car trunk. He said the vehicle has a trunk-release latch in the passenger compartment, as well as access to the trunk by pulling down the rear seat.

Rep. Merrill Cook, R-Utah, said Sunday that the deaths could speed legislation requiring release latches inside car trunks.

``It's such a terrible tragedy we need to make sure something like this never happens again,'' Cook said.

Supporters including Rep. Bart Stupak, D-Mich., have tried unsuccessfully for legislation requiring routine installation of trunk latches. Recent legislation requires the National Highway Traffic Safety Administration to study the benefits of such a law.

On July 13, four young cousins in Gallup, N.M., died of heat and asphyxiation in the trunk of a black car, which a doctor said could have reached 140 degrees. Relatives searching for the children drove the car for nearly an hour before finding the bodies in the trunk.

On Aug. 2, two young boys were found dead with two puppies in the trunk of their parents' car in Greensboro, Pa.

The five Utah girls will share a funeral on Wednesday. Thomas S. Monson, a top Mormon church official, will preside over the service.