Chicago police Supt. Jody Weis says the shooting involved gang members, and it came on the heels of a warning from police to gangs to stop the killing.
"My heart is breaking every minute of the day not knowing why him," McKinney's sister Nelli-Michel-le McKinney told ABC7, grieving for the brother she lost.
The 15-year-old was killed as he visited a classmate's Humboldt Park home. Witnesses say a stray bullet from a gunman chasing and shooting at someone else hit the high school student.
"She turned around, turned back to look at my son. He was holding his side, and he dropped down," said Vanessa McKinney, the victim's mother.
Darrell, also known as DJ, is the brother of the number two high school basketball player in the state, star athlete Mychael Henry.
"He was a good kid. He looked up to me. I was happy about that. I liked him a round. I just miss him. That's it," Henry said.
McKinney's death, along with another West Side attack Saturday night that left one man dead and another wounded, comes just weeks after a clandestine August 17th meeting between top law enforcement officials and the reputed leaders of several West Side street gangs at the Garfield Park Conservatory. ABC7 is told the police issued a warning: stop the killing, or else.
Sunday morning, police Superintendent Weis remained committed to stopping the violence.
"We just started this program. So, I don't expect all the shooting to stop overnight, but it's something we want to work towards. It's been successful in other cities," he said.
What appeared to be drug-dealing by gangbangers and the dice games that sometimes spark gun violence continued Sunday afternoon, leading some to question the effectiveness of the police department's gang violence reduction initiative.
Meanwhile, a family robbed of a loved one is forced to wonder about the reasons behind all of the violence.
"Please everybody, just come to a compromise. I just want it to be peaceful," Nelli-Michel-le McKinney said.