Another Great Expectation Question

The Question I have right now is: why is the other convict, Compeyson, trying to find Magwitch? Is he trying to seek revenge? This doesn't make sense because it was Magwitch who tried to stop him and he had tried to flee him, Magwitch even sacrificing his freedom to stop him from profiting. Maybe something happened in between theses time periods but it seems unlikely as he was sheep farming. If he is free again why would he want to find Magwitch?