Sarushka,
I'm at a disadvantage away from my Romanov books, but... Your Sablin photo prompts me to amend my post somewhat. I think he was a naval officer, not regular army. Knowing his rank would help confirm that. Also, his being mostly seen on board ships.
I also recall Sablin as being rather short and stocky, so your photo makes me wonder a bit. I' still accept your considerable wealth of knowledge.