ATLANTA (AP) — Police in suburban Atlanta say results of a toxicology report on a Georgia toddler who died in a hot car have come back with negative results, but officials won't specify which substances they tested for.

The child's father, 33-year-old Justin Ross Harris, faces murder and child cruelty charges in the June 18 death. Harris has said he left the boy in the SUV for about seven hours after forgetting to drop him off at day care.

Toxicology tests typically are used to detect foreign substances such as drugs in a person's system.

Cobb County police spokesman Mike Bowman said Friday that authorities aren't discussing further details of the results for 22-month-old Cooper Harris' body.