WATCH: Raw surveillance video of attempted carjacking, shooting
At a Monday afternoon news conference, police showed video from the popcorn shop showing the crime and the suspects in it. They encourage the public to slow the video down, look at it carefully, and to let them know if they recognize any of the suspects.
At least $34,000 is being offered as a reward for information leading to an arrest in the case.
RELATED: $8K reward offered for information on killers of retired Chicago firefighter Dwain Williams
Police said there are four suspects involved in the crime, though the driver of their car cannot be seen in the video because he never got out of the car. Police said the motive for the crime was carjacking, pure and simple.
"You saw three suspects exit the car," said Chief Brendan Deenihan. "We believe at least two of them discharged their weapons."
Police said Williams was making his regular visit to a Morgan Park popcorn shop when the father of four was murdered.
"Think about your father. What if this was your father?" said community activist Andrew Holmes.
WATCH: Chicago police, activists ask for information in murder of Dwain Williams
"We just want justice for the family. Here it is, he was trying to get some popcorn and his life was taken over a vehicle," said Early Walker, founder of "I'm Telling, Don't Shoot."
I'm Telling, Don't Shoot raised an additional $10,000 in reward money Sunday, bringing the total reward offered for information leading to an arrest in Williams' death to $34,000.
WATCH: CFD, CPD salute Lt. Williams as body arrives at medical examiner's office
Chicago police are now battling a dramatic increase in carjackings, with more than 1,200 reported so far this year. There were 501 reported at this time in 2019.
RELATED: Carjackings in Chicago increase 134% in 2020, police say
Detectives hope this video will help take some of those offenders off the streets and bring some peace to Williams' family.
Anyone with information that might lead to an arrest in Williams' murder can submit a tip anonymously at CPDtip.com.