Donald Courtney Biggs was being sentenced in U.S. District Court in Oregon when a man lunged over the railing to punch him in the face.
Biggs, 40, was sentenced to more than 15 years in federal prison for secretly videotaping minors while a youth pastor at the Mountain Christian Fellowship church, CNN reports.
Kevin Patrick Smith, a relative of two of Biggs' reported victims, said he "just kind of snapped" when he broke the defendant's nose.
U.S. marshals evacuated the courtroom and arrested Smith.
"I was on the ground as I was in handcuffs and I just started bawling on the ground," he said.
Jacob Elkin, another relative of a reported victim, said Smith, "was like a bolt of lightning just like Superman."
Smith was charged with fourth-degree assault, second-degree disorderly conduct and obstruction of judicial administration
Elkin is now rallying support for Smith's legal defense, starting a GoFundMe page that has raised $14,880 from 555 people.
"Kevin Smith is what I would like to call a heroic figure, a true man of justice, an outstanding man," Elkin said on the fundraising page.
"Long story short Kevin (father of two of the victims) did what every person in that room wanted to. He flew like the man of steel himself and punched Donny square in the face and continued to beat him until police pulled the two apart," he explained.
"In all seriousness Kevin has brought a little piece justice and helped all these victims feel better," Elkin argued.