Siale Angilau, a 25-year-old member of the Tongan Crips gang, was caught on camera as he calmly stood from his seat in a Utah courtroom, grabbed his lawyer’s pen and sprinted toward the witness.
A person in the court shouted “whoa, whoa, whoa” as Angilau leaped with his right arm cocked overhead with the pen in hand.
An officer standing over Angilau is heard shouting: “Drop the pen. Drop the pen out of your hand.”
While another yelled at Angilau: “Get on the ground.”
The US marshals then swung into action, firing four times at close range, killing te defndant.
The 24-second footage from the 2014 gang-related racketeering trial has only just been released after Angilau’s family launched a wrongful death suit.
They accused the marshall of acting excessively by firing four shots into a man who was only armed with a pen.
Their attorney, Bob Sykes, described the US marshall of “panicking”.
He said: “There was no need to use deadly force. They weren’t entitled to use the death penalty on him for an assault.”
But US District Judge John Dowdell cited the video as proof that the US marshal – who is referred to as Jane Doe in his ruling – acted reasonably.
Mr Dowdell said: “Having carefully reviewed the video of Angilau’s swift flight from counsel table, his vault over the witness stand with pen in hand, and his attempt to violently attack the shackled witness, the court has little difficulty determining that (Jane) Doe’s use of force to immediately stop Angilau’s attack was objectively reasonable under the totality of the circumstances.”
The shocking incident left a woman in the courtroom screaming in horror.
During the mayhem, police officers ran towards the witness stand.
Angilau’s defense attorney jumped under a desk while prosecutors stood in shock.
A bailiff swiftly moved to block the entrance to the front of the court and pointed at people in the gallery and told them to stay still with his right hand on his holstered weapon.
US District Judge Tena Campbell was then escorted out of the courtroom and someone called the emergency services.
The unidentified US marshal was cleared of any wrongdoing shortly after the shooting by the FBI.
And a review board found the use of force was justified.
Lynzey Donahue, a spokeswoman for the Marshals Service, said in a statement the video “demonstrates how quickly violence can erupt, in any situation”.
Angilau was one of 17 Tongan Crip members accused of of assault, conspiracy, robbery and weapons offenses.
He was the last defendant in the case to stand trial.
The other defendants were sentenced to 10 to 30 years in prison.