Prisoners from Arizona have been housed here since last month under an agreement between the two states.

DOC Commissioner J. David Donahue said at a news conference at the prison that the Arizona prisoners could smoke and enjoy other "cultural differences" before moving to Indiana, and that change had caused some issues in their comfort with the operations of the Indiana prison.

He also said guards did not go faster to quell the riot because "we didn't have anybody in harm's way."

The incident began when inmates from Arizona took off their shirts in a group display of noncompliance, Donahue told WTHR-TV (Channel 13) before leaving for New Castle.

Donahue said the riot ensued after a prison employee was knocked down. That person and a second employee were treated at a hospital for scrapes and cuts.

Donna Leone Hamm, executive director of Middle Ground Prison Reform, Inc. in Arizona, learned of the riot from a Star reporter but said she is not surprised.

Hamm said her organization has been contacted by inmates and their family members who said prisoners who were shipped off to Indiana with little notice, including some who said they were roused from their beds in the middle of the night and told to pack.

Arizona selected prisoners who were least likely to cause trouble, Hamm said. That meant well-behaved inmates felt they were being punished for playing by the rules.

In addition, some couldn’t bring along personal property, including televisions.

"What you basically have from the inmate population is an extremely agitated group of people who were literally plucked from the Arizona prison population, some on them in the middle of the night, and taken thousands of miles from their families. And they're not happy about it," she said.

"It's going to cause unrest," Hamm added. "Inmates are not known for being the most socially conscious or thoughtful people in the world. They will react. We're not condoning that they're doing this, but I don't think it's that much of a surprise, given to what I'm hearing about the abruptness."

Katie Decker, a spokeswoman for the Arizona Department of Corrections, said 630 male inmates are now housed at the New Castle facility.

Arizona had been expected to send more inmates, but Decker said that "has been put on hold."

"There were some prior things leading up to this as well that we were concerned about," she said.

Decker could not say immediately what those prior concerns were.