Motel owner spent 30 years spying on his guests' sex lives, considered himself a "researcher"

If a motel owner had found the drugs by some means unrelated to voyeurism and flushed them down the toilet, then if the man who discovered the drugs missing blamed the woman and killed her, could the motel owner really be charged with having any part in the murder in that case, assuming he would have had no reasonable expectation that flushing the drugs would lead to this? It seems unlikely to me the legal system would work that way, and I don’t see why the fact that he discovered the drugs through voyeurism would change his culpability for murder in this case. The motel owner might however be charged with failing to intervene when he actually saw the woman in the midst of being strangled, although he claimed that he thought she was still alive when the man stopped…but I’d guess that there is most likely a statute of limitations on failing to intervene in a murder since it’s a much lesser crime.