46-year-old Mindy Stephens, the wife of an assistant fire chief, is allegedly the stinky delivery woman in question ... according to KAXN, she pulled up in front of the Electra Police Department last month and made the drop-off.

Cops say an officer went out front to investigate, and found 3 5-gallon buckets -- weighing a total of 50 pounds -- filled with what appeared to be feces. He also observed Stephens in a hazmat suit walking towards an SUV with a trailer attached.

The officer reportedly asked her what she was doing ... and she allegedly told the cop she was dropping off the buckets of "human s***," and then drove off. A Lieutenant reportedly reviewed security footage and recognized Stephens' voice as the suspect.

Police say they contacted city officials about the issue, and said they'd call Stephens about picking the buckets up, but she allegedly refused -- telling officials it wasn't her problem.

Stephens was then charged with illegal dumping -- a Class B misdemeanor ... as well as a violation of the Texas health safety code. She was booked last week and was released the following day, after posting her $2K bond.

Believe it or not, this isn't Stephens' first run-in with the law, she reportedly got charged with aggravated assault back in 2020 after allegedly puncturing a man's hand and arm with a set of keys.