CHICAGO -- At least five people were gunned down Saturday in Chicago, including a 34-year-old man whose mother had already lost her three other children to shootings.Ronnie Chambers, who was his mother Shirley's youngest child, was shot in the head while sitting in a parked car on the city's West Side. A 21-year-old man who was also in the car was wounded, police said.Shirley Chambers, whose two other sons and daughter were shot in separate attacks more than a decade ago, was left grieving again on Saturday, WLS-TV reported (http://bit.ly/VCSh8i)."Right now, I'm totally lost because Ronnie was my only surviving son,'' Chambers said.Shirley Chambers' first child, Carlos, was shot and killed by a high school classmate in 1995 after an argument. He was 18. Her daughter Latoya, then 15, and her other son Jerome were shot and killed within months of one another in 2000."What did I do wrong? I was there for them. We didn't have everything we wanted but we had what we needed,'' she asked Saturday.Chambers said despite this latest tragic chapter in her life, she's not bitter or angry."They took my only child. I have nobody right now. That's my only baby,'' she said.A few hours after Ronnie Chambers was killed, a gunman opened fire on three men near a South Side eatery, killing two of them and wounding the third, police said. On Saturday afternoon, detectives were called to the scene of another shooting in which a man in his 30s and a teenager were shot to death. There had been no arrests.Chicago's homicide count eclipsed 500 last year for the first time since 2008. As grim as it is, Chicago's homicide rate was almost double in the early 1990s -- averaging about 900 -- before violent crime began dropping in cities across America.Last year's increase, though, stood in sharp contrast to New York, where homicides fell 21 percent from 2011, as of early December.