The prosecution rested Wednesday after a three-day trial and the defense declined to call any witnesses. There is no jury and the verdict will come from Circuit Judge James R. Clayton.
Watson is charged with punching Shane Farrell in the face Sept. 20 and then kicking him in the head outside a New Smyrna Beach skateboard park. Farrell was dead on arrival at a local hospital.
Watson was initially charged as an adult with second-degree murder, which would have meant at least 10 years in prison if he was convicted.
The charge was later reduced to manslaughter and he was tried as a juvenile. If he is convicted he will held until he is 21 years old.
Both boys were the size of an adult. Farrell is 6 feet tall despite his age, and Watson is 5 foot 10 inches.
Three confessions by Watson were presented in court -- one on videotape, one on audiotape and one in writing.
"I punched him in the jaw, and then I kicked him on the top of the head," Watson said on a videotape recorded inside a squad car.
In the written confession, taken an hour after the fight, Watson said: "The fight started because the boy Shane was giving my 8-year-old brother ciggerets, and tried smoking marijuana with him. He also made my brother steel him cigars from a convenient store. When I saw him he immediately said he didn't do anything like that and I didn't know what I was talking about.
"Then I punched him in the jaw and kicked his head, when he fell. I kicked him with the side of my foot," the written confession said.
Police said they went to Watson's home after the beating and entered Watson's bedroom. Officer Daniel Bass said Watson's younger brother was on the bed pretending to be sleeping, but raised his head and pointed at a closet where Watson was hiding.