I do have a bit of experience in this as I've dealt with both sides when I worked in mortgage lending - underwriting and repossessions.
We had a case where a husband murdered his wife at the house - well, he chased her out into the street and killed her there then dragged her back in. The first we knew of it was a solicitor called in to say she was deceased and he was in custody - no further details were given but we pretty much guessed what had happened (this was before the internet was invented otherwise I'd have been all over that as you can imagine) The mortgage was already in arrears and there was no life insurance so we repossessed the house. Part of my job was to call a few local estate agents to discuss the house and see who would do the best job selling it for us. The original agents who sold the house to the customers told me what happened. It was actually a fairly nice house but the problem was that, when any viewings took place, the neighbours would be over the fence telling the prospective buyers all about it. Nowadays, I believe it would have to be declared. Took ages to sell it (this was mid 1990's recession as well) but it did eventually sell.
When I was underwriting, I had a case where the surveyor, in his report, had mentioned something about the "chequered history" of the house - I knew immediately it would be a murder. I spoke to the surveyor and he confirmed (from memory) it was man who murdered his mother, his kids and then took his own life. My immediate thought was "No way am I lending on this" but the surveyor said that it would be good for the rental market and/or sale at the right price. It was a BTL mortgage with a fairly healthy LTV but I still really ummed and ahhed over it for a couple of days, especially with the thought of the previous case in my mind, but I did eventually approve it.
Bottom line - all houses will sell at the right price no matter their history.