U.S. Rep. Beto O’Rourke, the Democrat seeking to unseat U.S. Sen. Ted Cruz of Texas, called Friday night for the firing of a Dallas police officer who authorities say shot an unarmed black man in his apartment last week.

O’Rourke’s remarks came at a campaign rally ahead of his November midterm showdown against Cruz, FOX 4 of Dallas reported.

Last week, Dallas police Officer Amber Guyger, 30, allegedly shot Botham Jean, a black man, inside an apartment she mistook for her own. Guyger was booked in the Kaufman County Jail on a manslaughter charge three days later.

She was later released on a $300,000 bond and is awaiting trial.

At the rally, O’Rourke called for law enforcement to be held accountable and “do the right thing” in firing and prosecuting Guyger.

Earlier Friday, protesters gathered outside Dallas police headquarters, demanding that Guyger be charged with murder rather than manslaughter, FOX 4 reported. The group marched through downtown Dallas, stopping at various locations, before returning to police headquarters.

Jean’s mother, Allison Jean, on Friday denounced Guyger as “the devil,” and demanded she be fired, the Dallas Morning News reported.

Meanwhile, the campaigns of both Cruz and O'Rourke issued statements Friday evening, confirming they have agreed to hold three debates before the Nov. 6 election, the Houston Chronicle reported.

"To have my son smeared in such a way, I think that persons who are really nasty, who are really dirty and are going to cover up for the devil, Amber Guyger." — Allison Jean, mother of slain man

The first debate is scheduled for Sept. 21 in Dallas, with the others set for Houston and San Antonio. Each will be one hour, the report said.