Riddle: 3/9-3/15

Last week's riddle was:

"A man was to be sentenced, and the judge told him, "You may make a statement. If it is true, I'll sentence you to four years in prison. If it is false, I'll sentence you to six years in prison." After the man made his statement, the judge decided to let him go free. What did the man say?"
"Answer: You will sentence me to six years in prison. This made the judge so confused that she just decided to let him go free."

This week's riddle is:

"Two cops walked into a room with no windows and found a dead man who obviously hung himself from the ceiling, though they couldn't figure out how. There was no chair beneath him that he might have jumped off of, or a table. Just a puddle of water. How'd he do it?"