The suspect in a deadly shooting at a Florida video game tournament was known to barely speak to fellow gamers and sometimes exhibited an erratic playing style, according to other competitors, who were baffled that their virtual sport could lead to bloodshed. Authorities say 24-year-old David Katz of Baltimore killed two people and wounded nine others before fatally shooting himself Sunday at the “Madden NFL 19” tournament being held at a riverfront mall in Jacksonville.