FBI G-man, Jim Trailer first made an appearance helping Tracy bring the Famon Brothers to justice for their protection racket in 1935 and then helped apprehend Athnel Jones who was committed murders using ice bullets the following year. In 1938 Jim Trailer and Tracy teamed up to stop Karpse and Halone in their conspiracy to produce poison gas for a foreign power. Trailer was instrumental in bringing Karpse to justice. When a bomb is found at a post office, Dick Tracy and Jim Trailer join forces to track down the notorious Black Pearl who has been developing weapons and war machines at a mountaintop retreat. Trailer arrested Pearl and her gang. Jim would make brief appearances in later cases (such as the plot to destroy Diet Smith’s Fusion Plant) but rarely was he as prominent as his 1930’s roles.