What seems to be the underlying reason for the officer's suspicions about Jo? Can Jo be compared to our homeless population toady?

Jo has money on him. As a street urchin, this is unusual, and makes the officer think Jo might be up to no good or have gotten the money illegally. Today, although we have a substantial population of homeless, children are no longer allowed to live in the streets and fend for themselves. We have social services that protect them.