Beaver County Judge John Dohanich ruled Monday that prosecutors cannot proceed with a charge of aggravated assault against Thomas Grant, 24.
Defense attorney Steven Valsamidis challenged the charge, saying it required proof of malice. He has characterized the shooting of the 8-year-old girl as a "tragic accident."
Police said the child was in a black costume with a white feather or tassel on her hat during a Halloween party at a New Sewickley home in October.
According to police, Grant said he thought she was a skunk. He was also charged with reckless endangerment and simple assault.