WICHITA FALLS, Texas (AP) _ A woman stabbed her 5-year-old son to death, then called the boy's grandmother, who found his body, police said.

Arvelia Oliver, 27, was arrested Friday on a murder charge, a few hours after her son was stabbed at their home in Wichita Falls.

Police are still investigating a motive for the stabbing. They said Oliver was suffering from a drug overdose when emergency medical workers found her at a truck stop near Wichita Falls.