The morgue van is abandoned in a well worn and familiar LA River, but in 1947 channelization (turning it from a natural river to the straight and concrete lined one) was still very much in progress, especially through the middle of town where this apparently happened. It would have been an active construction site, or possibly brand new with construction immediately adjacent, not at all as shown.
Channelization was not in fact completed along the entire length of the river through the city until 1960.
Channelization was not in fact completed along the entire length of the river through the city until 1960.
The villain at the bar of the dance hall is supposed to be inconspicuous, but he is wearing a hat. Ballrooms had hat-check services and men did not wear hats indoors. This made him extremely conspicuous.