Anecdotal, but growing up in a generally low-income rural area, I don't remember any of my peers not having a computer in the early 90s. Many of them, including myself, even had computers into the mid-80s and some of those families were quite poor, even by local standards.
The internet came later, but games like Doom were huge long before that, which is pertinent as you mention violent crime specifically.
The internet came later, but games like Doom were huge long before that, which is pertinent as you mention violent crime specifically.