For what it is worth, my contacts in the exotic hunting trade are having good hunting. Also a friend that just likes to hunt a lot has recently taken wild turkey, feral hogs, and something that looks like a big black cat eating a small peccary.

Could be a game cam pic or photoshopped, but is interesting.

It looks like a jaguar to me. I have seen reports of a few males making up to Arizona and Deep South Texas.

Or it could have got loose from someone’s maniageria.

Jaguars are commonly melanistic!

Update:
The rancher emailed this and other game camera pix to my friend Joe after he had hunted the ranch and taken Javelina. Rancher did not actually see the cat, but did get the picture from one of his game cameras. The ranch is in far Southwest Texas where the animals cross the border as they please.
Such pix make hunting the area a little bit more interesting.

Joe just called and he is driving to Hondo to help a friend who owns a high fenced exotic ranch and has a client there shooting game faster than he (the owner )can get it collected and hung in the cold room. Dang, I would drive down and help if not for stitches in my right hand and more doctor and dentist appointments next week.

Having ranched on the border of far west Texas, bordering the Big Bend Nat'l. park, and a couple miles from Boquillas Mexico I realize that animals do cross the river from time to time. The last grizzly was shot South of Marathon some 75 years ago, and never has a Jaguar been sighted that I know of short of rumor..If that was a Jaguar even the black ones show spots if you look close, and from the shape of the head I suspect its a Mt. Lion with a black gene, a freak of nature..Other than that the picture is just too posed with the Javalina head in mouth etc. and Ive never seen a Lion kill wherein the predictor packed off a head. that Javalina head is cut pretty clean. looks like some one cut off its head to me. Most of the decapited kills Ive seen had a lot of hide hanging off the head, not chopped off. Just my opine, right or wrong..

No melanistic (black) mountain lion has ever been known to science. It just doesn't happen.

That is a jaguar.

His head is too broad to be a lion anyway.

I would like to see the game camera picture that the friend of your friend has.
The picture you posted is of a Jaguar in a zoo.

I don't like to say someone is telling you a tall tale, but I don't see a melanistic jaguar being on cam in Texas. Non-melanistic in Arizona, occasionally. And why would it carry a head around and how would it decapitate the javelina? The body is where the meat is not the head...