I just watched the movie Compulsion, staring Orson Welles and other well-known actors. I don't want to discuss the movie itself, just one aspect that seemed illogical (which I have a tendency to be bothered by).

So the prosecutor was trying to locate the owner of a pair of glasses and narrowed it down to three people based on something to do with its unusual hinge. But he didn't mention comparing the strength of the lenses to the prescription of the suspect, which would seem to have been a better way to match them to the owner. It seemed like such an obvious thing was overlooked. Is there an in-universe explanation for this?

1 Answer 1


Compulsion is based on a real-life murder case: the murder of Bobby Franks by Nathan Leopold and Richard Loeb in May 1924. As in the film, Leopold dropped his glasses at the murder scene, and as Wikipedia explains:

Although common in prescription and frame, they were fitted with an unusual hinge purchased by only three customers in Chicago, one of whom was Leopold.

Presumably, the same explanation holds true in the film: the glasses' prescription was common enough that it was no help in narrowing down the suspects.

  • Interesting. I just think it could have been mentioned that all three people had the same prescription and it matched that of the glasses, if that was the case. Dec 13, 2022 at 0:53
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    @Not_Einstein Looking at the Wikipedia references for the source case, the hinges were used to identify the manufacturer, and from there to the retailer. The three people were those who bought the glasses from the retailer, so the hinge type was used to narrow it down to those three suspects (two men and one woman), not to pick the final one out of the three.
    – Gary Myers
    Dec 13, 2022 at 5:08
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    @Not_Einstein: I may be way off, without a better historical understanding of the 1920s, but it would not surprise me if prescription glasses were expensive, or prescriptions imprecise enough, that it would not be uncommon for people with a variety of different needs for glasses to have very similar glasses, in much the same way as today, a lot of people will make do with cheap Dollar Store magnifying lenses. Dec 13, 2022 at 13:16
  • @Gary Myers: But why wouldn't they want to pick the final one out of the three if they could, based on the prescription? It's like knowing a suspect wore a particular jersey and they narrowed it down to a few people who had such a jersey but didn't bother to check the size. But as as has been pointed out, in those days it would be assumed many people had the same prescription, so I guess that explains it. Dec 13, 2022 at 15:30
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    The cited source in Wikipedia, from UMKC Law article has some more details. Perhaps because Leopold already had a connection to the case, they had enough reason to suspect.
    – jpa
    Dec 13, 2022 at 18:25

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