A routine traffic stop in Harford County led to the discovery of a suspected methamphetamine lab in a Joppa hotel room, police said.
About 11:30 p.m. Thursday, Valarie Ann James, 24, of Goldsboro, N.C., was arrested in the 900 block of Pulaski Highway.
Sheriff's deputies found a 30-pound cylinder - containing anhydrous ammonia, a product used in the manufacture of methamphetamine - and suspected methamphetamine and marijuana in the back of her 1994 Oldsmobile.
As a result of the investigation, sheriff's deputies and federal drug enforcement agents searched a Super 8 motel room in the 1000 block of Pulaski Highway.
There they found materials and components used to manufacture methamphetamine, as well as a shotgun.
James and two men - Thomas James Roman, 27, and Donald Ross Evans, 21, also of Goldsboro - were arrested on federal charges of conspiracy to manufacture methamphetamine and weapons charges, police said.