I'm not the one murdering them, quite literally. Just like in real life, there is no mystical unstoppable force of nature in play. It's another person, like you. Their choices aren't your choices.

To put it another way, if you sold a kid a bike and he later crashes and dies despite the bike having no faults, are you responsible? Most would correctly identify that you are not responsible in that scenario, as the kid is responsible for what they did with the bike.