I'm convinced it can happen. Bear in mind, though, that for a truly "stealth" woman - no one knows and there's no hint to her past - it may not ever make the news that that was why she died. If the only person who knew was her murderer when she confided in him, and he chooses NOT to reveal that as part of his trial (or is never caught/tried)...
We're not supposed to post links, but you can Google for stories about Mayang Prasetyo (murdered by her husband, be warned that the story is extremely graphic), Victoria Carmen White (the man who was tried and acquitted for her murder on insufficient evidence was a guy she met in a bar and took home, and prosecution argued that the revelation of her gender identity [at 10 years post-op] was the reason for her murder), and a Russian post-op trans woman named Kamilla murdered when her boyfriend went through her things and found an old letter (which seems to match what you had in mind). I found that in the first couple pages of search returns, and if you'll excuse me, I'm too depressed to continue now.
Violent men will seize on any excuse to be violent, and violent trans/homophobic men who are afraid their equally bigoted friends will mock them might be even more easily provoked. Of course, dating men like that is probably a risky idea anyway, but sometimes a woman doesn't know until it's too late.