The new prison is using all of the following security methods EXCEPT______.

The Brazilian government has opened the first in a new generation of federal high security prisons which it hopes will help stop gang leaders continuing to operate from behind bars. It’s part of a long term program but follows an outbreak of violence in Sao Paulo which was ordered by jailed gang commanders and resulted in at least 120 deaths.
    Inmates will be held in individual cells under video surveillance. Guards will wear clip microphones so their conversations with prisoners can be recorded. And X-ray machines will be used to spot guns, explosives and drugs. Brazilian officials will also hope the new prisons help them tackle 2 other problems with the country’s jails: riots often between rival gangs and escape bids which frequently get help from guards. But there is one potential problem: the Sao Paulo violence was sparked by dispute over the detention conditions of PCC leaders. It’s unlikely that any gang commander would go quietly to the federal government’s new jails.