Peacemakers, on USA Network
IMDb; TV Tango; Wikipedia

Set in the 1880s, the show is about Federal Marshal Jared Stone, whose new deputy, Larimer Finch, is a former Pinkerton agent from Chicago who uses new forensic techniques. They are often assisted by the local mortician, Katie Owen. Katie is also raising her younger sister Amy. Another recurring character is a teenager called Chipper, who helps out sometimes, because he'd like to become a marshal himself, someday. The show didn't last very long and I don't remember it well, but I know I rather liked it while it was originally on.