SAN RAFAEL, Calif. » A former San Rafael waitress is facing charges after law enforcement authorities say she sold cocaine and methamphetamine to undercover investigators posing as restaurant customers.

Marin County Deputy District Attorney Sean Kensinger says 41-year-old Francisca Avina sold the drugs to undercover detectives eight times during the course of the investigation at Playa Azul Marisco restaurant.

The Marin Independent Journal reports (http://bit.ly/PFfWUy) Avina and her alleged drug supplier, 32-year-old Alvaro Ucan-Piste of Richmond, are scheduled to be arraigned Monday on several charges related to narcotics sales.

The pair was arrested during a bust Wednesday night following an investigation by the county’s Major Crimes Task Force.

Investigators say they found a quarter pound of suspected cocaine on Ucan-Piste and also found cocaine and cash in a search of Avina’s residence.