10 of the deadliest spree killers in history of the world (With Pictures)

9. Mark O. Barton

On July 29th, 1999, Mark O. Barton, a daytrader at Momentum Securities walked into his office and opened fire, killing four people. Then he went next door to All-Tech Investment Group and killed five more people. He fled the scene and ended up committing suicide before the police could apprehend him. When his apartment was searched, it was discovered that he’d also murdered his wife and their two children. He was also previously a suspect in the murders of his first wife and her mother, but was never charged. Authorities believe the stress over losing $105,000 in the month prior to the attacks is what triggered Barton’s rampage.