While the SFPD has yet to confirm the motive behind last Friday's murder of 58-year-old construction worker Mitzi Campbell, NBC Bay Area is now reporting that the dispute leading up to the fatal stabbing may have centered around the use of a Porta-Potty—possibly connecting it to another stabbing that occurred in the Tenderloin two weeks ago, over an identical dispute.

According to NBC's report, the woman who allegedly stabbed Campbell—23-year-old Lizette Cauich, of Los Angeles—became angry after Campbell refused to allow her to use the Porta-Potty at the construction site where Campbell was directing traffic, at Fifth and Shipley streets.

Cauich was arrested just after the stabbing, alongside 42-year-old Oscar Mendez, also of Los Angeles. Mendez was found with the knife allegedly used in the killing, and was arrested on warrants, narcotics and weapons charges.

NBC's sources have alleged that Cauich and Mendez are the same couple behind the stabbing of a man at Eddy and Taylor in the Tenderloin two weeks ago. That stabbing, which resulted in life-threatening injuries, was also preceded by a dispute over the use of a Porta-Potty.