A toddler and a man were fatally shot while riding in a car in a Valentine's Day attack captured in a live video on Facebook.
Police said Wednesday that they were still searching for a suspect in the shooting which shocked Chicago, a city grappling with a surge in violence so severe that it has drawn the condemnation of President Donald Trump.
The two-year-old boy, identified by officials as Lavontay White, was shot in the head on Tuesday and died at a hospital.
The boy was riding in the back seat of a red sedan, with his 20-year-old aunt and a 26-year-old man in the front, when another man began shooting at them, according to authorities.
Officials have not publicly named the pair, who were live-streaming their car ride on Facebook as shots rang out.
The woman can be seen screaming and running out of the car and into an alley, as multiple shots are heard in rapid succession. Images of the vehicle showed multiple bullet holes.
The man, who also died of a gunshot wound to the head, was the intended target of the gang-related shooting, police said.
The woman, who was reportedly pregnant, was wounded in the stomach and survived.
"This has just got to stop somewhere," police chief Eddie Johnson told news media on Tuesday.
"Our children shouldn't have to keep paying the price for our inability to hold repeat gun offenders accountable for their actions," Johnson said.
"I'm sick of it, and I know Chicago is sick of it."
Johnson has repeatedly blamed lax sentencing of repeat gun offenders as a major reason why police struggle to stem the Midwestern city's raging violence, which authorities have attributed largely to gangs.
The shooting on Tuesday was one of three in a particularly difficult period of just a few days, which saw children fall victim to shootings.
On Saturday, a 12-year-old girl was wounded and an 11-year-old girl killed in separate incidents. Police on Wednesday said they had charged a 19-year-old man, a known gang member, in the latter case.
Trump has repeatedly criticized Chicago's violence, and tweeted that he would "send in the feds" if the city did not fix the problem.
So far this year, there have been 63 murders in Chicago, more than double the number for the same time period two years ago. And last year, there were more than 750 murders and 3,500 shootings - levels not seen in Chicago in two decades.
Mayor Rahm Emanuel has said he would welcome federal help and additional funding to complement the efforts of local law enforcement.