On the first meeting between sergie and the beggar, the beggar was wearing a fawn coloured overcoat and said sergie that he had not eaten for three days and had been a school teacher who lost his job due to bad plans. As the beggar explained these things, sergie recognizes that they had met before on Sadovya street and that the beggar was an expelled student. Sergie then threatened him by saying that he will call the police.

The beggar tells Sergei that he had lost his way and had been looking for his sister's house for two days. He explains that he is from a village near Moscow and had come to the city to find work. However, he got lost and ended up wandering the streets without any money or food. He had been begging for two days, but no one had helped him.

Reason for Sergei threatening to call the police:
Sergei threatens to call the police because he suspects that the beggar is lying and trying to take advantage of his kindness. He finds the beggar's story suspicious and believes that he may be a fraud or a thief.

Explanation in detail:
- Sergei is a young boy who comes from a well-to-do family. He is walking home from school when he encounters the beggar sitting on a bench.
- The beggar approaches Sergei and asks for some money. Sergei, feeling sympathetic, gives him a few coins. However, he notices that the beggar is not like the usual beggars he has seen before.
- Sergei describes the beggar as well-dressed and clean, unlike the typical image he had in his mind of a beggar. He also notices that the beggar is wearing expensive shoes and a gold ring.
- When Sergei questions the beggar about his situation, the beggar tells him the story of how he lost his way and had been looking for his sister's house for two days.
- However, Sergei finds the beggar's story hard to believe. He points out that the beggar is well-dressed and wearing expensive shoes, which seems contradictory to his claim of being lost and in need of help.
- Sergei becomes suspicious and threatens to call the police, hoping to scare the beggar away. He believes that the beggar may be trying to deceive him or even steal from him.
- The beggar, realizing that Sergei is not falling for his story, quickly changes his tone and leaves, avoiding any confrontation with the police.
- Sergei's suspicion and decision to threaten the beggar with the police demonstrate his discerning nature and ability to question the authenticity of people's claims.