Chester earned his bone early Monday when he detected nearly nine kilos of marijuana in luggage from a bus that had traveled from Guápiles to San José.
Police officers and the Unidad Canina of the security ministry are making spot checks at local bus stations. The discovery of the marijuana was at the Caribbean station in the center of the capital.
Police also discovered a pistol with the drugs. No one was detained because the owner of the shipment was not clear.