YAKIMA, Wash. — An effort by Yakima police to search buses coming to town is paying off, authorities say.

Separate searches by drug dogs since Saturday led to the discovery of about 13 pounds of cocaine and about 4.5 pounds of heroin, said Capt. Rod Light of the Yakima Police Department.

The drugs were found in backpacks abandoned on buses coming to Yakima from near the California-Mexico border.

The bus company, Fronteras del Norte, has informally agreed to let the police department’s drug dog handlers run searches on the bus when they arrive, Light said.

“They work with us proactively to prevent and certainly dissaude this type of activity,” Light said.

The drug haulers apparently leave their cargo behind when they spot officers in the area as passengers are getting off, Light said.

The cocaine found in the Saturday search had an estimated street value of $151,000, he said. The heroin found Monday was in powder form, which is uncommon for this area, making its value harder to estimate.

Other law enforcement agencies have also seized drugs from Fronteras buses, Light said. A search in Toppenish by a Lower Valley drug task force yielded 22 pounds of cocaine; a total of 20 pounds of methamphetamine was seized in two other cases.

Light said that even though no arrests are likely in the recent cases, it’s still worthwhile to remove the large quantities of illegal drugs from circulation.