The two major gangs in the prison, the Chicanos and the Aryan Brotherhood, decided to attack Cell Block 4 which was used to house sex criminals, snitches, ex-cops, and other inmates considered unsafe to put in general population. There were 96 prisoners held here. The rioters were especially interested in exacting revenge on the snitches. However they first had to pass the psychology office and it was raided for psychiatric drugs which were widely consumed and distributed to other inmates. The rioters also started a fire in the office to destroy psychiatric records used as a pretext to deny inmates parole.

The rioters did not have a key to enter Cell Block 4 however a nearby block had blowtorches that were left there as part of construction work. They used them to cut through the security grilles, a tedious process that would take hours so until then some rioters went off to raid the records office and find out the identities of snitches. Rioters with walkie-talkies detailed their plans to get revenge on them. The segregated prisoners yelled at state police outside to save them but the police did not attempt to make use of a back door they could have walked out of as it was only for emergency use and they did not have the keys for it. The police also agreed to not enter the prison as long as the correctional officers being held hostage were still alive.