blog questions

In the beginning the book was hard to understand, but after getting used to the language and how the characters talk about the Great Expectations became a ted bit interesting. What I dont get though is at the end of the third chapter (pg. 19) when the 1st convict says "Where is he?...I'll hunt him down like a blood hound." The convict is talking about the man Pip said he saw in the marshes before giving him the food. Why is this man scared of there being another convict in the swamp?