Well, it's straight from a citation from Loyola Law School. Following the citation takes us to Maya Lau's article titled, "Inked with a skull in a cowboy hat, L.A. County sheriff’s deputy describes exclusive society of lawmen at California station"[0]. This article makes no mention of The Executioners or the tattoo they use. For that you need to look at another LA Times article titled "After decades of problems, new allegations surface of a secret clique within L.A. County Sheriff's Department".[1] If we find the relevant quote in that article here's what we get.
"Aldama described a tattoo on his calf as a skull with a rifle and a military-style helmet with flames surrounding it. On the helmet are the letters “C P T” for Compton."
So at some point "military-style" was switched to nazi. I don't know why, but since there's apparent conflict let's do our own research. Googling Nazi helmet gave me plenty of images, and they generally have a large flare on the back and the brim turns up. The helmets also seem to typically have badges on the side and I didn't see any that had a band on them like in the tattoo. I think these helmets look far more like the type worn by US troops in the Vietnam war.
[0](LA Times) https://www.latimes.com/local/lanow/la-me-palmdale-sheriff-t...
[1](LA Times via Archive.is) https://archive.is/gNquP