I can't see any matching genus of Dexiini. The combination of M ending in wing margin, T1+2 with small excavation and no median marginals, and first flagellomere long rules out almost all genera, and the remaining ones don't look like this.

The hairy parafacial and extra notopleural bristles are also typical of Sarcophagidae, and the shape of the bend in M is not typical of Dexiini.

Touché. Sorry for moving it prematurely. I'm not entirely convinced it didn't show median marginals on syntergite 1+2. The image isn't in sharp focus at that plane, and I'd like to see a sharper image of this area to check for sockets, before ruling it out.

How many notopleurals do you see? I see two.

Marci, do you still have this fly? Any chance of some sharp photos of the scutellum (to check for the presence of a subscutellum underneath) and of the base of the dorsal abdomen?

In the lateral view follow the row of strong anepisternal bristles to the top. Ahead of the top of the row are three strong bristles on the notopleuron.

Keys to Sarcophagini or Boettcheriini in MND depending on the postalar wall. (That's why I consider Sarcophagidae impossible -- there's almost always something ambiguous or invisible.)

The Nearctic Manual to Diptera key for Sarcophagidae should probably be less emphasized. Pape has discussed some of its problems in the world catalogue and the failure to designate some type specimens has left me further skeptical of it. I don't think the character for the frontal setae are helpful. The key in Manual to Central American Diptera is a significant improvement and probably excludes few genera, if any at all, from the Nearctic (even though some of the features needed may still be difficult, at least the post-alar wall is not the first couplet).

Yes, I will get a few more photos as you request tomorrow and post.

I don't know that. I looked at Marshall's book and see racing stripes on Calliphoridae and Tachinidae. Frankly, I struggle to put flies in families so will defer to you and others.