Rearrange the details for better flow. I don’t know who ever said starting a logline with “When something happens” but it’s terrible and doesn’t make sense that so many people use it without listening to how slow and boring it sounds.

Always start with the protagonist – no one cares about events, we care about people. Aside from how it’s phrased, all the pertinent details are here: protagonist, antagonist, conflict, stakes. Just put it in a more compelling order without punctuation and it’s solid.

A cranky veteran must uncover the truth behind several unexplained deaths in his retirement village before the widowed suspects make him the next to go.

This doesn’t quite identify the tone – could be dark comedy, could be dramatic thriller – but does generate interest in reading more, so as long as the tone is clear in a synopsis or summary or treatment or especially the script, it’s fine.