The shocking incident took place inside Fargo’s Quentin Burdick Courthouse after the jury had returned a partial guilty verdict against the man on terrorizing-related charges, say officials.
Witnesses said that the jury had left the courtroom, but that US District Judge Peter Welte, courtroom staff and others were still inside.
North Dakota US Marshal Dallas Carlson said the man, who has not been named, had been armed with a sharp plastic object at the time of the incident.
“He produced an edge[d] weapon and cut his throat,” Carlson told local news outlet KVRR.
FBI spokesman Kevin Smith said the man had been acquitted on one charge and found guilty on the other charge, and was about to be taken into custody.
“He did the self-harm after he heard the verdict and after the jury had left the courtroom,” Mr Smith told the Associated Press.
“We need to officially document what happened in that federal courtroom today,” he added.
“All the questions you have, we have. What was the sharp object, how did it get into the courtroom – those questions – what did people see him do?”
Smith confirmed that the FBI had opened an investigation into the incident, as has the US Marshals Service.
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