Out of San Patricio county.

Two Mathis convenience stores have been caught selling synthetic urine used to pass drug tests.

According to investigators, both stores were caught selling the product and a drink used to mask marijuana use for over a year in violation of state law.

A 2015 Texas law amendment bans selling "synthetic urine designed to falsify drug test."

Officials say the drink is used to mask drug tests by cleaning out the users system. Two clerks, each from both stores, are facing charges of falsifying results of a drug test.