FORT WAYNE, Ind. (WANE) - Investigators believe the person who pulled the trigger in the recent shooting that killed a 17-year-old at a party acted in self-defense. Willie Venzell Ivy III, a student at North Side High School, died after being shot at a northeast side home Saturday night. Investigators revealed Thursday that Ivy was allegedly the person who fired nine shots first, according to a joint statement between the Fort Wayne Police Department and the Allen County Prosecutor's Office. The commotion began around 10:30 p.m. in a neighborhood off Reed Road between Saint Joe Center and Stellhorn roads. A high school Halloween party in the 4900 block of Manistee Drive "quickly got out of hand", the press release said. An advertisement for the party allegedly told attendees - many of whom were teenagers - to bring their own alcohol and marijuana. According to the release, the homeowner eventually went to their bedroom and locked the door but didn't call police. Delphi: Tip marked ‘cleared’ found while cleaning out desk put Richard Allen on the radar in 2022 Officers later learned partygoers were patted down for weapons before being able to go in the house. But investigators determined Ivy came to the party with a group of friends and they allegedly went to the back door to avoid being patted down, according to the release. Two other people - who would eventually be shot - "tried to stop Ivy and his group from entering, but they began forcing their way into the home," the release said. At some point, Ivy allegedly pulled out a handgun and began firing shots from the back door, through the kitchen and into the living room, according to the release. Nine people were hit by the gunfire and their injuries were reportedly non-life-threatening. Fort Wayne Community Schools said in a statement several students in the district were among the injured. "Physical and ballistic evidence, medical records, autopsy reports and witness statements showed that nine of the shooting victims were struck by gunfire from Ivy’s handgun," the release said. A man who'd been shot returned fire, according to the release, shooting Ivy. The release said Ivy was found in the yard of a home and was pronounced dead at the scene. "This man will not face criminal charges as his actions were justified under established Indiana self-defense law," the statement read. Investigators at the scene witnessed "utter chaos", as described in the release, with teenagers scattering everywhere away from the home. FWPD detectives spoke with over 40 witnesses and reviewed crime scene documentation and ballistic evidence, medical records, Allen County Coroner’s Office autopsy findings, as well as surveillance and social media video footage. The release noted that other criminal charges may be coming as the investigation continues.