A secret is only a secret if it isn't shared. With anyone.
It's not even that someone can't be trusted to want to keep your confidence; people tell secrets by accident. They didn't mean to tell.
We don't really know that this is what happened in this case, but the article says that a woman "let slip a remark" that gave police the clue.
From the Arizona Daily Star, Friday, Sept. 3, 1937:
THEFT SUSPECT ARRESTED HERE
Woman's Remark Said to Have Resulted in Police Trap
A woman's remark last night trapped a man who police accused of the bold theft responsible for robbing the Daniel's Jewelry store of nearly $800 in watches and gems five days ago.
The man said he was Bill Chamberlain, 29. Officers declared he gave them a full confession.
After Chamberlain hurled a paper-wrapped brick through the store window early Sunday morning and scooped up nine watches and several rings, he fled down Stone avenue and made his way to the Heidel hotel, where he was registered under another name, police said he told them.
A squad car called to the scene came within a block of him before he reached safety, Chamberlain was quoted. The man was seen by only one person, Manuel Soto, Arizona Daily Star newsboy of 226 East Sixteenth street.
Two days after the robbery, police said, a woman-friend of Chamberlain let slip a remark that was overheard, and officers were notified.
They watched Chamberlain two days, finally arresting him last night. The man confessed after 20 minutes of questioning, the police declared.
He led them to his loot, which was hidden in his room inside a camera. Chamberlain, the officer said, told them he had served three prison terms in Alabama, one for manslaughter and two for robbing safes. He came to Tucson from that state two weeks ago.
Chamberlain was booked on a charge of night-time burglary.
If the man was only 29 at the time he was arrested in Tucson and had already served three prison terms in Alabama, he must have started his criminal career at quite a young age.
