Update: Here is a screenshot of the Texas DPS ten most wanted for July of 2015. Note that 9 of the ten have Hispanic surnames. Immigration status is not stated. It is interesting to note that all ten are classified as "White".
This does not prove the 2/3 number, but it does support it. If the 2/3 number is accurate, we would expect the majority of the ten most wanted to have Hispanic surnames. It also shows that in the criminal justice system, the term "White" has little or nothing to do with cultural heritage. For criminal justice purposes, Hispanic criminals are considered "White", but Hispanic victims are classified as Hispanics.
Here are some numbers from 2014 in California(pdf). Hispanics were 47% of arrestees for murder in the state. We do not know the immigration status.
Total California arrests for homicide in 2014. 1,427
- 20.1 percent (287) were white
- 46.0 percent (657) were Hispanic
- 27.2 percent (388) were black
- 6.7 percent (95) were other