Florida shooter Nikolas Cruz walked around campus wearing an orange backpack emblazoned with a racial slur and a swastika more than one year before the mass shooting that left 17 people dead, a former Marjory Stoneman Douglas High School student testified Monday. 

Jurors were shown a photograph that Kyle Horrigan snapped in September 2016, showing the hateful message scrawled in sloppy black letters above a swastika: "F--- you N-----." 

" I was personally shocked by it, that someone would walk around in public with that, much less at a school," said Horrigan, who didn't personally know Cruz. 

Horrigan, who now works as firefighter, was called by prosecutors in the state's rebuttal case at the penalty trial in Fort Lauderdale.

JUDGE LASHES OUT AT DEFENSE LAWYERS AFTER THEY RESTED THEIR CASE

Nikolas Cruz in court and his orange backpack with a racial slur written on it

A photo combination of Nikolas Cruz in court Monday Oct. 3, 2022, for his penalty trial and a backpack emblazoned with a racial slur that he once wore to school. (Amy Beth Bennett via AP/ Law&Crime)

Earlier Monday Broward County Circuit Judge Elizabeth Scherer had a testy exchange with defense lawyer Tamara Curtis out of the jury's earshot over the admissibility of a letter that Cruz had written.

Curtis asked if she could question the witness about the letter.

 "I’m not going to tell you how to do your cross-examination," Scherer said after exhaling deeply in exasperation. 

Judge Elizabeth Scherer speaks sharply calling lead defense attorney Melisa McNeill "unprofessional"

Judge Elizabeth Scherer having a heated courtroom exchange with Nikolas Cruz's defense lawyer Melisa McNeill Sept. 14, 2022, outside the earshot of jurors. (Amy Beth Bennett/South Florida Sun Sentinel via AP, Pool)

Jurors were played clips from Dr. Charles Scott's jailhouse interview with Cruz in which he described the painstaking planning he put into the Feb. 14, 2018, massacre that killed 14 students and three staffers.

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Cruz said he was inspired by the 1999 Columbine High School shooting and chose Valentine's Day for his rampage because he has no one to love. A girlfriend broke up with him 18 months before the attack.

Marjory Stoneman Douglas High School

Students are evacuated by police from Marjory Stoneman Douglas High School in Parkland, Fla., during the shooting that took place there in February. (AP/South Florida Sun-Sentinel)

"I studied mass murderers and how they did it," he told Scott, a prosecution psychiatrist. Scott said that Cruz is a sociopath who can control his behavior but chooses not to because he has no regard for others. 

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The trial, which began July 18, will only determine whether Cruz is sentenced to death or life without the possibility of parole. He pleaded guilty to 17 counts of first-degree murder and other charges in October of last year.