According to one broadcast TV station's unnamed sources, the SoMa construction worker who was stabbed to death last week might have been murdered by an LA couple because she refused to allow them to use the job site's porta-potty, the second such alleged attack by the duo.

You likely caught a bit of the story last week: At around 9:30 a.m. Friday, 58-year-old construction worker Mitzi Campbell was directing traffic at the South of Market intersection of Fifth and Shipley Streets, when witnesses say they saw her arguing with a couple near the job site.

As Campbell escorted the couple, since identified by the San Francisco Police Department as 23-year-old Lizette Cauich and 42-year-old Oscar Mendez, away from the construction site, witnesses say that Cauich pulled out a weapon and stabbed Campbell multiple times.

Though the couple allegedly led, they were pursued by Campbell's co-workers, and were arrested near Fifth and Folsom Streets.

Campbell was rushed to San Francisco General Hospital, where she succumbed to her injuries and died.

But while Gatpandan could not offer any additional information on the motive behind Campbell's slaying, Chron investigative scribe turned NBC Bay Area reporter Jaxon Van Derbeken has unnamed sources who claim that a job site porta-potty was the source of the dispute.

According to NBC's report, "Cauich became angry when Campbell refused to allow her use of the construction site toilet" and that authorities have since linked Cauich and Mendez to a similar attack in the Tenderloin on May 29.

As reported by Bay City News on May 31, that attack occurred at 1:30 p.m. near Eddy and Taylor streets, when "a 23-year-old woman and a man of unspecified age, asked the victim to use a portable toilet located in a lot in the area."

When the man turned them down, they allegedly "stabbed him in the upper torso with a knife," leaving him with life-threatening injuries.

According to Bay City News, both are scheduled to be arraigned in San Francisco Superior Court on Tuesday afternoon, and will face charges in both crimes. Mendez faces charges of attempted murder, mayhem, assault with force likely to cause great bodily injury, battery with serious injury, carrying a dirk and dagger, possession of a controlled substance, receiving or buying stolen property and giving false information to a police officer. Mendez, who like Cauich is a resident of Los Angeles, is also the subject of LA County arrest warrants for assault with a deadly weapon and domestic violence, Gatpandan says.

Cauich's charges include murder, attempted murder, mayhem, assault with force likely to commit great bodily injury, and battery with serious bodily injury. Both are, according to a San Francisco County Jail spokesperson, presently being held without bail.

Previously: Female Construction Worker Fatally Stabbed In SoMa