Looks like Hadrurus spadix upon first glance at that picture you posted. But can you post a few more just to confirm that?
You should stick to using the scientific name for it, common names don't get too far because they can mean any number of different species. I can think of at least half a dozen off hand that I could call a black back scorpion.
Either way, Hadrurus are not deathly lethal to humans, The Only Exception would be those that are allergic to the Venom. If you wanted to keep the Scorpion you could. Otherwise, take it someplace safe and Let It Go.
Definitely Hadrurus spadix. Very nice find! If you're still wondering how to differentiate the two species, Hadrurus arizonensis have a yellow half-circle shape that goes around their eyes, and Hadrurus spadix lack this mark, so they're completely dark. That's the easiest way to tell the two species apart