Now, his father has been charged with shooting three people in Chicago, police spokesman Anthony Guglielmi told CNN.
Pierre Stokes, 25, faces three counts of aggravated battery with a firearm and one count of unlawful use of a weapon by a felon in the shootings last week.
Two of the victims were treated and released; a third suffered a graze wound and refused medical attention.
Stokes was charged Sunday and is set to appear in court Monday for a bond hearing, said Guglielmi. It wasn't immediately clear whether he'd retained an attorney.
"This represents the challenge that police grapple with. We are aggressively working to hold gun offenders and gang members accountable," the spokesman wrote in an email to CNN.
"Mr. Stokes, who was involved in a gang lifestyle, ultimately suffered an unspeakable loss with the calculated execution of his son. Despite this, he continued to engage in the same gang activity that started this cycle of retaliatory violence."
A second suspect was charged in the boy's killing last week.
Dwright Boone-Doty, 22, first planned to kidnap and torture Tyshawn by cutting off his fingers and ears, Cook County State's Attorney Anita Alvarez said then.
Alvarez said that Boone-Doty made statements about how he approached Tyshawn at a playground and invited him to a store to buy the boy something.
Two other suspects were with Boone-Doty before the killing and met with him afterward to purchase cleaning supplies in an attempt to sanitize the vehicle they used that day before abandoning it, Alvarez said.
The first suspect, Corey Morgan, 27, was arrested in November and charged with first-degree murder. At the time, police said Morgan didn't act alone, but with two others, including one who was in custody on an unrelated charge. Boone-Doty is the suspect police were referring to.
The third suspect, Kevin Edwards, remains at large, Guglielmi said.