They identified the suspects as a 21-year-old man from Leesburg, Florida, and a 21-year-old man from Texas.
Cops say the men placed the Christmas tree in front of the buoy and lit it on fire between 3 a.m. and 3:30 a.m. on Jan. 1.
The Key West Fire Department extinguished the fire. However, authorities said the blaze caused “extensive damage” to the landmark.
The buoy has sat at South and Whitehead streets since 1983 and purports to mark the southernmost point in the continental United States. It is a popular spot for tourists to take their pictures while on the island.