The families of two black Chicagoans killed by police accused officers on Sunday of having used excessive force and Mayor Rahm Emanuel of having failed them, piling pressure on a city facing a U.S. federal probe over possible racial bias in policing, according to Reuters. Police shot Quintonio LeGrier, 19, a male college student who was visiting his father, and Bettie Jones, a 55-year-old mother of five, on Saturday. Family members said police were called after LeGrier threatened his father with a metal baseball bat. Jones, who lived in a first-floor apartment, was shot through the door, said her cousin Evelyn Glover. Police said LeGrier was being combative. They said Jones was killed by accident and extended condolences. "This needs to stop. No mother should have to bury her child," Janet Cooksey, LeGrier's mother, told a news conference in front of the home. She said her son was shot seven times. She previously told reporters her son suffered from mental illness. Several people who spoke wore T-shirts reading, "Rahm Failed Us." Speakers demanded to know why police used lethal force. In a statement later on Sunday, Emanuel called for a review of the police Crisis Intervention Team and improved guidance for officers handling cases where the mental health of a person is a factor. "There are serious questions about yesterday's shootings that must be answered in full by the Independent Police Review Authority's investigation," his statement said. High-profile killings of black men by police officers since mid-2014 have triggered waves of protest - including in Chicago, the country's third-largest city - and fueled a civil rights movement under the name Black Lives Matter. About 100 people including religious leaders held a vigil in neighborhood streets, with many saying they did not trust the police to be truthful about what happened. "Trigger- happy cops are still engaged in senseless murders of people of color," Ira Acree, pastor of the Greater St. John Bible Church, said at the vigil. A Chicago police video of the fatal shooting of another black teenager sparked protests last month, with activists demanding the resignation of Emanuel, a former chief of staff to President Barack Obama. A federal investigation is under way over the department's use of deadly force and officer discipline. Police said an unspecified weapon was recovered. They did not say whether there was a video of the incident and provided no information on officers involved.