Wonder Man (1945) on Netflix

Plot summary

The Dingle brothers are twins who look almost indistinguishable but have not seen each other in years. Despite the resemblance, they have very different personalities. Buster, loud and goofy, performs at the Pelican Club under the stage name Buzzy Bellew, while Edwin is a studious, quiet bookworm at work on a history book. Buster witnesses a murder by the mob boss Ten Grand Jackson, and Jackson's men kill him soon after, leaving him in the lake at Prospect Park. Buster comes back as a ghost and summons Edwin to the park, asking his brother to help bring the killer to justice.