Maurice Harris, who faces four counts of first-degree murder, was denied bail on Wednesday and due back in court on April 25.
Police said he was taken into custody late Tuesday night, five days after he allegedly shot up Nadia Fish and Chicken at the corner of East 75th Street and South Coles Avenue.
"As we have seen too many times before here in Chicago, he's no stranger to CPD. Nor is he unfamiliar with using an illegal handgun," said Chicago Police Supt. Eddie Johnson during a press conference.
However, Harris' mother said Wednesday her son has an alibi. Tamika Harris said she has phone records to prove she was talking to her son at the time of the shooting. She said her son could not have been near the restaurant because he was at the coroner's office, identifying his father, Jerry Jacobs. Police said they stand by their arrest.
Cmdr. Brendan Deenihan said Jacobs, 37, was fatally shot the day before the restaurant shooting, in the 7900-block of South Phillips. Jacobs was walking on the sidewalk about 11:15 p.m. when four men got out of a dark-colored van and shot him, police said at the time. Deenihan said "a reasonable person would believe" the two shootings were related.
"I think a reasonable motive would be that his father got killed and subsequently he shoots and kills these four people," Deenihan said. "Does he do that randomly? Only he can answer that question. I wouldn't suspect he just picked four random people on the street. That wouldn't make sense to me."
Harris has not given a confession and was arrested Tuesday near 127th and Western, said Deenihan, who added that several eyewitnesses told police Harris was the only shooter.
Emmanuel C. Stokes, 28, and Edwin Davis, 32, were fatally shot inside the restaurant.
Two other men, 19-year-old Raheem Jackson and his 20-year-old brother Dillon Jackson, ran from the restaurant as gunfire erupted, but both were fatally shot in different parking lots within a block of the restaurant, authorities said.
All four were pronounced dead at the scene, according to the Cook County Medical Examiner's Office. Stokes and the Jacksons lived in South Shore; Davis was a Brainerd neighborhood resident.
Dillon and Raheem Jackson had gone to the restaurant to visit their mother, who has worked there for eight years, according to their grandmother, Georgia Jackson. She said she lost another grandson to gun violence in 2011.
"I can't keep doing this," Georgia Jackson said. "I'm losing too many kids."
"Despite the fact that we know these incidents were tied to gang conflict, it doesn't lessen the weight of what happened," Johnson said.
"It certainly doesn't make me, as a Chicagoan and as the leader of this department, any less angry and disgusted at the destruction some individuals are willing to cause by their own hand. It puts under the spotlight exactly the problem that's at the heart of the violence we see in this city: illegal guns and the individuals willing to use them because they don't fear the consequences of their actions," Johnson said.
The superintendent said this is Harris' first arrest as an adult, but he has encountered Chicago police before.
"While I can't go into the specifics, into his extensive juvenile history, as we've seen too many times before here in Chicago, he is no stranger to CPD. Nor is he unfamiliar with using an illegal handgun," Johnson said.
At a gathering called "Operation Wake Up" near the murder scene Tuesday night, Alderman Gregory Mitchell (7th Ward) joined police and community members to condemn violence plaguing the neighborhood.
"To date, as an adult, I've lost 36 of my childhood friends to this garbage and these streets. Thirty-six of them and another 17 in jail that I still talk to and they wish they hadn't done that dumb stuff," Mitchell said.
CPD Commander Darren Doss reminded the community he can only make the streets safe if people start talking.
"If you see something or you want to tell me something, call me. Call any officer. Sign up. It can be anonymous. We just need to know. We just need to take these streets and do what we need to do," Doss said.
"I continue to call on our legislators, our community members and the families of those who contribute to the violence to work with us to get them on the right path before they act and to hold them accountable if they choose to pull a trigger," Johnson said Wednesday.
The four men killed in the restaurant shooting were among seven people gunned down in three separate shootings within a mile of each other in less than two days last week.
Johnson said investigators are still working to determine whether the restaurant shooting was connected to a shooting that occurred later that night, where two people were killed.
So far in 2017, 150 people have been murdered.
The Sun-Times Media Wire contributed to this report.