A 15-year-old girl is in custody and police are appealing for another youth involved in a violent assault in Barrie to come forward.Investigators say around 10 p.m. on July 31, they were called to Lakeshore Drive and Victoria Street where they discovered a 16-year-old girl suffering from non-life threatening injuries. Police say she has since been treated for her physical injuries and released from hospital.“Through the investigation, police learned of a video circulating on social media of the assault. Barrie Police are deeply concerned, not only by the violent nature of the assault, but also by the actions of those who witnessed it,” they said in a release. “Several individuals crowded around as the assault took place cheering, encouraging the aggressors, and recording on their cell phones.”“In moments of crisis, choosing compassion over clicks can make a critical difference.”Police arrested a 15-year-old and charged her with assault.Investigators say they are aware of a second youth who is believed to be involved in the assault and they are asking them to contact the police.Police are unable to release the names of those involved due to the Youth Criminal Justice Act, and that those restrictions also apply to social media, adding it is a serious offence to “publish, post, or share identifying details about a young offender or any witnesses or victims under the age of 18.”