Yesterday I found this little guy where I found Theif. He is not a Red-sided Garter Snake, so what is he?

Based on the snakes in my state, he could be:

Checkered Garter Snake - Thamnophis marcianus
Western Ribbon Snake - Thamnophis proximus
Plains Garter Snake - Thamnophis radix
And this is what I don't think he is:
Common Garter Snake - Thamnophis sirtalis

Pictures coming soon, but for now a description since my camera is recharging:

About 4 inches long, orange on the sides does not appear as on Thamnophis sirtalis, no yellow or white dots on head. Irregular black ticking near belly in a stripe that follows the cream colored stripe on it's back.