A convicted Oklahoma prison architect who had helped design a prison system that housed hundreds of inmates for years has been sentenced to prison for five years and six months.

Key points:Robert P. Allen, 62, was sentenced to five years in federal prisonHe was the prison architect for the Oklahoma City prison where dozens of inmates were housedHe was found guilty in March of arson and criminal mischiefHe has been barred from doing work in Oklahoma and ordered to pay restitutionThe Oklahoma Bureau of Investigation says the fire at the prison was set by inmate arson, but Allen’s defense said that was a fabrication and he was a victim of political retribution.

“Mr. Allen was the person who put together the prison system to hold people who were going to prison,” said Assistant U.S. Attorney David Fuchs in a statement.

“He created a system that put hundreds of people in prison.”

Allen’s attorneys had argued that he was the victim of a political retribution campaign and the federal government was trying to destroy his reputation, but prosecutors rejected that argument.

“There was no political retribution,” Fuchs said.

“There was a desire to create an atmosphere that led to the riot.”

Allen was convicted in March for setting the prison’s fire on April 3, 2015, but he was not charged with arson.

The blaze was set to help inmates with their medical needs, and the prison had been designed by prison architect and architect consultant David A. Allen.

The fire was a response to a dispute over the way inmates were sent to the prison.

It caused an estimated $40 million in damage and forced the closure of the prison in the fall of 2015.