Prosecutors on Friday appealed a Tokyo District Court ruling that cleared a doctor of failing to give proper treatment to a 4-year-old boy who died after a cotton candy stick pierced his throat and penetrated his brain in 1999.

The prosecutors said the district court ruling on March 28 that acquitted Hideki Nemoto, a doctor at Kyorin University Hospital in Mitaka, western Tokyo, on March 28, incorrectly evaluated the evidence submitted to show a causal link between the boy's treatment and death.

In its ruling, the court agreed with prosecutors that Nemoto failed to properly treat the boy, but "the chances that the boy's life could have been saved were very slim, even if the defendant had noticed that part of the stick remained in the boy's brain."

According to the ruling, Shunzo Sugino fell over with a cotton candy stick in his mouth at a festival in Tokyo's Suginami Ward on July 10, 1999. The stick went through the boy's throat and into his brain.

The boy was taken to the hospital, but sent home later in the day. He died there the following day from the injury.