NEW : Inmate unrest at the prison in second stage . NEW : Authorities : Three inmates have been killed ; one has severed finger . Prison was site of another prison riot in 2014 . CNN 's Janet DiGiacomo contributed to this report . Officials said they do not know what sparked latest riot .
NEW : Inmate unrest at the prison in second stage . NEW : Authorities : Three inmates have been killed ; one has severed finger . Prison was site of another prison riot in 2014 . Officials said they do not know what sparked latest riot .