There's always a question after tragedies like the December, 2022 shooting at a condo in Vaughan that left six people dead, including the shooter: "How did nobody see this coming?!"In this case, the killer had long held a grudge against the members of the condo board he fired upon. He was known around the property as an angry man, and had a history of domestic abuse and violence. In hindsight, all the signs were there—but that's what makes mass shooters so easy to see in the rearview mirror, but almost impossible to see coming...GUEST: Michelle Henry, reporter, The Toronto Star (Read Michelle's investigation here.)