Complex sentence: Dale claims to have caught the Bandit, and Hank sees that Dale is the Bandit as by his expression, and decides to "let him escape", with the promise that he will not try anything such as this again.
Split into simpler sentences: Dale claims to have caught the Bandit, and Hank finally realizes that Dale is the Bandit. He decides to "let him escape", with the promise that he will not try anything like this again.