"He had to hit him. That's how the whole thing started," Nigg said.
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Steven Nigg, 60, is serving time at Englewood Prison in Colorado for a weapons conviction and reportedly instigated the prison yard scuffle that left Fogle with facial bruising, a bloodied nose and neck abrasions, according to PEOPLE.
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Steven Nigg's family tells KMGH the convict was upset by Fogle's 15-year sentence stemming from his guilty plea in November to one count each of distributing and receiving child porn and traveling to engage in illicit sexual conduct with a minor.
"He doesn't regret it at all, that's why they won't let him back in the yard," Jim Nigg told KMGH. "He would do it again."
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Critics have complained that the light prison sentence didn't fit the crimes Fogle pleaded guilty to.
"It bothered him any way you look at it, but yea I'm sure it's not, it's not fair, it's not equal," said Nigg.
As a result of the prison brawl, Steven Nigg was placed in "the hole" -- solitary confinement -- and remains there since the attack. Nigg's "good time" was revoked as punishment for the beating on Fogle, his brother said.
The U.S. Bureau of Prisons would not confirm the assault or punishment "based on the need to ensure safety and security in our institutions and in accordance with legal requirements including the Privacy Act," a spokesman said.
Jim Nigg spoke out to PEOPLE that his brother provoked the attack.
"He can't figure out why you would do that to kids," Nigg said. "He says, 'I can't be around those people.'"
According to the Nigg family, Steven has had previous run-ins with child molesters in prison and that they are raising funds in an attempt to get him out of prison.
Nigg's life of crime began in his early 20s including a 1976 armed robbery spree in Arizona.
Fogle is expected to end his sentence and leave Englewood Prison five years after Nigg serves his time.