At the end of In a Lonely Place, when Capt. Lochner calls to announce Dix Steele’s vindication and (needlessly) apologize for his persistent investigation of Dix as a murder suspect, Laurel Gray tearfully responds, “Yesterday, this would have meant so much to us. Now it doesn’t matter. It doesn’t matter at all.” This suggests that the strain of the murder investigation was the catalyst for her love affair with Dix unraveling, as if it might be a reasonable excuse for his attempt to strangle her just moments before for planning to leave him. It’s not a stretch to think she might believe this – domestic abuse victims frequently make excuses for their abusers – but one comes away from In a Lonely Place wondering if the film wants us to believe it.
Long before his final tantrum, it had already been clearly established that Dix is a violently insecure man under the best of circumstances. If anything, the murder investigation did Laurel a favor, alerting her to his true nature earlier than she might have found out otherwise. So why is this framed as a tragedy of circumstance? Why include the murder mystery at all? The tragedy isn’t that a happy ending was thwarted, it’s that there was never any chance for a happy ending in the first place.