The French Connection ending explained (spoilers)

[BryceReeni]

Popeye and Russo find out that drugs are hidden in the rocket panels of Charnier's Lincoln Continental. Meanwhile, Charnier takes his car to a drug trade on a small island with only one entrance. When Charnier leaves, he gets to the end of the bridge and finds Popeye, waving to him. The cops then chase him back to the island, where Russo and the cops have a shootout with the other drug dealers. Popeye chases after Charnier who leads him into an abandoned crematorium. Popeye shoots at what he thinks is Charnier, but in actual fact, he shot Mulderig (the cop he hated so much). Popeye tells Russo that he saw Charnier and that he will find him. He runs off deeper into the crematorium, until he is out of sight. A gunshot is heard, and the screen goes black. An epilogue tells us that Charnier got away, and Popeye and Russo were transferred out of Narcotics and reassigned.