Unraveling the Mystery of the Michigan State Shooter's Motive and Timeline

The man who killed three students at Michigan State University had no connection to the school and bought the ammunition only a few hours before the attack. The motive for the attack remains unknown, despite the killer leaving a note complaining about feeling rejected and not having sex in a decade. The shooter had no known ties to the university and had not applied to work there. The incident is one of over 170 mass shootings in the US so far this year, prompting renewed calls for gun control measures.