Because technically, Hispanics are Caucasian. But in the US, many do not identify as such, nor are they treated as such by a significant number of the US population.
They are an ethnic minority and, depending on the ethnologist you're consulting, they're a racial minority as well. But most of them are descended from western Europeans, specifically those from the northern half of the Iberian peninsula so they are technically Caucasian Whites.
We have several regular users here, for example, that would throw a giant hissy fit and be mortally offended if you dared to call a Hispanic a Caucasian.
So for demographic cataloging purposes and for multiple other reasons, it is easiest in the US to distinguish between Hispanic Caucasian and Non-Hispanic Caucasians. The term 'Caucasian' would be inferred automatically by any LEO reading the arrest record and seeing Non-Hispanic.
In this particular case, however, they could have simply omitted the Non-Hispanic and said "Carolina White Trash" just as easily. The penitentiary is very likely to be the first home this inbred, murdering, meth-addled cunt has ever lived in that didn't have wheels.
Or worse yet, sitting on cinder blocks.
