A switch, which is a device that alters the trigger to continuously fire, was likely used during the Memorial Day mass shooting in Fairmount Park that killed two people and left nine injured, police said on Tuesday. Although the weapons used in the shooting have yet to be recovered, investigators believe a switch was used, based off of analysis of social media posts of the tragedy, said Philadelphia Police Commissioner Kevin Bethel. However, the investigation is ongoing and police say they hope that the number of people at the park at the time of the shooting ultimately leads to information that helps them find the perpetrators.