Crime scene: 162 mystery solving puzzles to find out who the murderer is

Chapter 108 Case 1257
At dawn one day, the Public Security Bureau of a certain city received a call to report that 50 yuan had been stolen from the credit union.Director Gao of the Public Security Bureau immediately appointed several smart and capable comrades to form a detection team, and issued an emergency notification to the city's transportation, transportation, post and telecommunications departments.

At around 10 o'clock the next night, Director Liu of the Post and Telecommunications Office of the development zone hurried into the gate of the Public Security Bureau with a few telegrams. Said: "Chief Li, just now there was a man who sent 10 telegrams all at once, all with the same content, only the four numbers '1257', I think this is a bit strange, do you see Is it related to that case?"

Section Chief Li took the 10 telegrams from Director Liu and looked at them. Indeed, they were all the same. They were sent to several nearby districts and counties, and the names and addresses of the senders were the same.Section Chief Li immediately called a meeting of all the scouts on duty to study. After analyzing the content of the telegram, everyone finally came to the conclusion that the sender was a criminal.

How did the public security personnel determine that the reporter was a criminal based on the content of the telegram?
[Answer] In order to hide, the criminal did not use clear words in the telegram, but used the four notes "1257" in the numbered music notation as the password, which is the homonym of "all come to receive information", and informed his accomplices to come to his house To divide the stolen money.

(End of this chapter)