CHICAGO -- Two people were killed and two others were wounded in a shooting at party on the south side of Chicago. A 16-year-old girl who witnessed the shooting suffered an asthma attack at the scene and later died.The Cook County Medical Examiner's Office identified two of the people who died overnight: Jessica Williams, 16, of the 12000-block of South State Street and Denzel Childs, 25. Authorities did not release his address. The identity of the third victim, a 33-year-old woman, has not yet been released.Police said a group of people were gathered in the 800-block of West 50th Place in Chicago's Back of the Yards neighborhood just before 12:20 a.m. Thursday. That's when someone walked up, fired several shots and ran away.The 33-year-old woman was shot in the neck. She was rushed to St. Bernard Hospital, where she was pronounced dead. Denzel Childs suffered several gunshot wounds to the neck, hand and chest. He was transported to Stroger Hospital, where he was pronounced dead.Paula Griffin Golden, Childs' mother, said he was a father of two and that he was killed over a parking space someone wanted from him. She couldn't believe someone would take her son's life over something so petty."I'm still numb. I can't believe it. I mean why? Why couldn't you just move your car? If somebody's got to park, why can't you just drive on by?" Golden asked.A 25-year-old woman was shot twice in the back. She was also taken to Stroger, where her condition stabilized. A 21-year-old woman was shot in the left hand. She was also taken to St. Bernard, where her condition stabilized.A 16-year-old girl who saw the shooting suffered an asthma attack at the scene. Police said she was rushed to St. Bernard, where she was pronounced dead at 2:05 a.m.Police said Childs and the 25-year-old woman were documented gang members and a witness is not cooperating. Area Central detectives are investigating. No one is in custody.The crime scene on West 50th Place stretched from South Peoria to South Halsted. Dozens of people, ambulances and about 15 squad cars were scattered along the street early Thursday. A man could be seen crying and walking away on South Halsted with a female and two officers.A woman, who preferred to remain anonymous, claimed to be the aunt of the 25-year-old woman who was shot. She said the party was a memorial for a friend who was shot to death about four years ago. About 75-100 people were at the party outside, grilling food and drinking.She was across the street when she saw a man and someone else arguing."It was like someone who was from over here arguing with someone who probably wasn't from over here," she said.She said as other people got involved, the first man pulled out a gun fired into the air before more people started shooting. She later saw the man getting rolled away into an ambulance."When I saw him pull the gun, I ran to a porch...and chilled there until it was safe," she said. When the shooting stopped, she "heard everyone hollering 'this person got shot and this person is shot and this person is shot."She said her niece is a mother of four and a hard worker.Another party-goer, James Hughes, said the shooters were part of a faction of the Almighty Black P Stone gang called the Moes, who "saw a fight (break) out and they fed off it."When the shooting started, Hughes said he saw more than 50 people try to run away. He took to the ground and tried to shield a friend whose "brother and father are already gone."