Is there any forensic analysis of these proposed marks?
They should all be measured and placed together for comparison
Star man
I did send the photos to an expert. Here is his answer:
In the case of Dyatlov, it seems to me that this simply coincided because of the angle.
On photos from other angles this mark is not legible, although abrasions of a different shape are visible. The size of the outlined pattern is larger than what you can see as similar to this mark on the rest of the cases, which I don't believe is a mark at all.
Doroshenko has a putrid venous network on his hand, and the isolated U is more likely just a fragment of it.
The U shaped mark in question can be only seen on Krivonischenko's leg, and this is not the best image. It's like a Rorschach test - you can pick up another detail and try to match it on other bodies.
I don't find the mark you're asking for to be repetitive on other bodies.