Danny drives Helen's neighbor Laury back to her place but she's not yet ready to call it a night ... "Come on in ... let's have a nightcap".
Then ... Her house had appeared earlier in the movie during the daytime, the middle one, below.
... and Now, CitySleuth has searched unsuccessfully in Reno
for this location; of course it could have been filmed elsewhere, probably in Southern California. Anyone who recognizes it is encouraged to contact email@example.com.
Inside the house Laury's other boyfriend Sam lurks in wait in the kitchen and in no uncertain terms tells Danny to clear off. A brief but shockingly ferocious fight ends with two fatal poker blows to Danny's head.
Laury hears the noise and comes in ... stunned by what she sees, she turns around and recognizes Sam. But dead witnesses don't talk and it's the audience's turn to be stunned when she is quickly dispatched in the same way with the same poker.
Shortly after Sam leaves, Helen stops by and discovers the chilling scene. Her reaction is surprisingly impassive but even more odd is what she does about it, or rather doesn't do, returning to her lodging room next door but refraining from calling the police. Instead she quickly packs and heads to the station for the late train home to San Francisco.