OROFINO -- A 33-year-old Orofino area woman has been arrested for involuntary manslaughter and felony injury to a child after a 15-month-old boy was found dead in a locked car in temperatures approaching 100 degrees.

Rita Johnston, the child's stepgrandmother, remained in the Clearwater County Jail on $15,000 bond Thursday.

Clearwater County Prosecutor Clayne Tyler said an investigation showed that the child was in the car for about five hours when passers-by noticed him and called authorities.

The infant was pronounced dead at the scene around 6 p.m. Wednesday

Clearwater County Public Defender Jack Hathaway represented Johnston and said his client was distraught.

The identity of the child was not immediately available, pending notification of relatives.