Sheriff’s deputies searching a commercial passenger bus with a K-9 unit on Tuesday morning uncovered nearly 16 pounds of heroin — all of it hidden in two fire extinguishers.

The deputies pulled the bus over for a traffic violation on I-12 and searched the luggage compartment for drugs with a dog named Jumma, said Casey Rayborn Hicks, a Sheriff’s Office spokeswoman.

When Jumma alerted the deputies to a narcotic odor, the deputies found the two fire extinguishers that held 7.2 kilograms — or 15.8 pounds — of heroin in plastic bags, Hicks said.

Deputies arrested Juan Vasquez, 26, of McAllen, Texas, on a count of possession with intent to distribute heroin.