(Harrah-AP) -- The parents of a suspended Harrah High School student are challenging the school's drug policy.
Byron and Sonja Wilkins filed a federal lawsuit Wednesday after their son Byron Keith Wilkins the Third was suspended after refusing to take a drug test.
The school's drug dog made a hit on Wilkins' backpack in March.
After school officials removed a -- quote -- "unknown substance" from his backpack, the lawsuit says Wilkins was asked to take a drug test.
But he refused it at his father's urging and was suspended.
School officials sent the substance to police, but the lawsuit claims police could tell the substance wasn't illegal and didn't bother to test it.