in conjunction with that, we can establish whether or not the guy is a gang member. >> raymond diaz is about his gang-related tattoos. >> the stuff i got on me, a lot of it is gang related. they call them like stamps, you know. everything was done behind bars with a staple. we don't use fancy needles and all that. the main part on my chest, it's blast, dongo blast. it's probably one of the biggest prison gangs in texas. i chose to put it in big letters on my chest because when i get to a prison unit or a pod or something the first thing i do is i take off my shirt, and it's clearly visible. if someone has a problem with me, they're going -- they're going to let it be known. >> diaz is also a tattoo artist and says he has applied many of his tattoos himself. most are gang related but one is a fan tribute. >> which is my taylor swift. i did her for my own personal gratification. i don't know what it is about her but the first time i heard her voice, i was locked up. i would listen to her music and she's got like this really, cute, country voice. it soothed me. no matter what's going on,