The relatives of two black people who were fatally shot by Chicago police officers demanded answers from Mayor Rahm Emanuel on Sunday, amid escalating tensions over allegations of racial bias in policing. Quintonio LeGrier, 19, a college student who was visiting his father, and 55-year-old Bettie Jones, a mother of five, were killed by police Saturday. Police responded to a call after LeGrier allegedly threatened his father with a baseball bat. Jones, who lived in the first-floor apartment, was shot through the door, according to her cousin Evelyn Glover. Janet Cooksey, LeGrier’s mother, joined family members at a press conference Sunday, demanding to know why police used lethal force. The police department is under federal investigation over officers’ use of deadly force.