A Slippery Conundrum

A man is found hanging from a rope in a room with no windows and
only 
one door. The door is the only way to enter or exit the room and
it is 
locked, barred and bolted from the inside. The man has been dead
for hours 
and his feet are a good three feet off of the floor.
The detectives who arrived on the scene were stumped since other
than the 
fact that the floor was covered in water, there was nothing else
in the room 
at all?

Was this a suicide or not?
Why?