The case did indeed collapse - due mainly to the fact that two detectives brought in to solve the case by the duke of Windsor, failed abysmally in their task and created much controversy with their questionable investigation...
Captain James Barker andCaptain Edward Melchen came from Miami at the Duke's request, as the former King of England did not think the local force up to the job.
The problems arose as follows: They forgot to bring a fingerprint camera with them to the Bahamas.
They allowed locals onto the crime scene, who subsequently handled objects in the room. Vital evidence was lost as a result.
Barker was accused by de Marigny's defence at having planted the fingerprint on the Chinese screen - Barker was unsure where exactly it had been located on the screen. He also admitted to having lied about taking fingerprints from everyone who had entered the crime scene. He didn't.
With so many holes in the investigation and with multiple suspects, including also the businessman Axel Wenner-Gren, (he had alleged links with the Nazis and could have had Sir Harry killed if he had unearthed information about this) and the Duke of Windsor (for the same reasons...), the jury had no option but to throw the case out of court. There was no evidence to prove any theory and many seemed implausible anyway.
On November 12, 1943, de Marigny walked away a free man.