Lafitte ran the most successful smuggling and privateering operation on the Gulf, from Barataria Bay and then from Galveston, and when the US Navy finally pushed him out in 1821 he burned his settlement and sailed. That exit is why every bay and bayou from Louisiana to Texas has a Lafitte treasure story. He was real, the wealth was real, and no cache has ever been authenticated. Treat the stories as coastal folklore with a genuine pirate underneath, and note that Galveston Island and the Louisiana marshes are mostly private or protected ground.
Galveston Island and the Louisiana coast
See it on the map