GREAT FALLS, Mont. -

A 48-year-old Great Falls woman has denied causing the overdose death of her 1-year-old grandson this summer.
    
The Great Falls Tribune reports Tracy Ann Harless pleaded not guilty Thursday to negligent homicide in the death of Riley Padilla.
    
Court records say Riley died on July 28 of an overdose of the narcotic pain medication oxycodone that would have been fatal for an adult. The boy's autopsy also indicated the presence of cocaine.
    
Charging documents say a test of Harless' blood indicated she also had oxycodone and cocaine in her system.
    
Prosecutors say Harless was babysitting her grandson the evening of July 27, while the boy's mother went to the fair.