SAN LUIS OBISPO, Calif.—Authorities say 15 people have been arrested in the takedown of a drug trafficking ring suspected of dealing large amounts of heroin in San Luis Obispo County.

The county sheriff's office said officers from multiple agencies participated in Wednesday's raid, and they seized an unspecified amount of narcotics, guns and money.

The raid was the culmination of an investigation in which detectives had already seized about 2 1/4 pounds of heroin and an ounce of methamphetamine with a street value of more than $100,000.

Authorities said the ring operated out of Paso Robles, Atascadero, San Luis Obispo and several other cities in the area, and had direct ties to Mexican drug cartels.