Frederick County authorities are investigating the death of a 5-month-old baby who was left alone in a parked car for several hours, a sheriff's deputy said yesterday.

Isaiah C. Brown died Thursday afternoon shortly after sheriff's deputies and emergency workers went to his family's home on Iverson Terrace North in response to an "infant cardiac arrest" call from the father at 2:29 p.m., Deputy Jennifer Bailey said.

The child died at Frederick Memorial Hospital a short time later, Bailey said.

Investigators are trying to determine why the child had been left in the car, a four-door Buick, for "several hours" and where the father had been with the child that day, Bailey said.

No charges have been filed.

The family lives in the Spring Ridge community, just outside the city, and has three other children, Bailey said.

The father, Ralph Brown, has served on the board of the Frederick County Department of Social Services, State's Attorney Scott L. Rolle said. The agency's Web site lists him as a board member.

Rolle said it appears that the father, who was handling the daily routine of dropping the children at a bus stop, school and day care, might have become confused when one of the children missed a bus. But many questions remain, he said.

He said that investigators estimate that the temperature inside the car reached 125 degrees.