Police in Kalamazoo now have three people in custody in connection with the fatal shooting Monday evening of 13-year-old Michael Day.  Police initially arrested an 18-year-old person-of-interest on unrelated charges but say their investigation revealed that three different men fired guns in the direction of the victim.  Investigators believe the fatal shot came from a shotgun wielded by 15-year-old Victor Garay; he was charged with Open Murder yesterday.  A 23-year-old man was also arrested and a handgun was seized from his home.