city. >> a specialized group of officers is responsible for monitoring gang activity. this is the investigative services unit or isu. >> i've been spending a lot of time challenging isu to get out and take the lead. be the spear tip out there to challenge gangsters and tell them, you can't do that on our yard. >> we're tasked to cover anything that affects institutional security. gang activity, in-prison drug trafficking, responding to disturbances, crime scene investigations. prison gangs tend to cause the most problems here in the institution, so they're mainly our focus. >> we will be putting cuffs on. so we're going to put cuffs on him and then get him out. >> if you're working in prison, this is the best job to have. these guys are self-motivated. they're out the door handling something before i even get the chance to tell them to go do it. >> i'm the runt. i'm the baby. i'm the rookie.