The victim, Carvajal, was gunned down after leaving a Fourth of July party in the city's Belmont Cragin neighborhood in 2021.
Carvajal's family said police arrested Joseph "Troubles" Matos soon after the murder, but the state's attorney's office determined there was insufficient evidence to file charges.
The U.S. attorney has since filed racketeering and gun charges against Matos.
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The FBI has raised their reward from $25,000 to $50,000 for information that leads to the arrest and conviction of Matos. They said he should be considered armed and dangerous.
Carvajal was just days away from his 20th birthday when he was killed. He was a member of the Army National Guard, and also hoped to go the academy and become a Chicago police officer.
Investigators have said they're not sure Matos is still in the Chicago area. But they're hoping the increase in the reward will move the needle and finally get Carvajal's family the closure they seek.
Investigators believe the shooters, who did not know Carvajal, were trying to elevate their status in their Northwest Side gang.
"My mom takes in the hardest. It's a daily struggle. And we continue to find the strength within to not only mourn his loss, but also fight for justice," sister Jennifer Ramírez said.
Matos and Gary Roberson were federally charged in connection with Carvajal's murder three years ago.
Roberson was taken into custody.
Matos remains at large.
"There is a possibility he's still in the Chicagoland area, but he does have connections to the greater Dallas area, California. And there are rumblings and we've had leads out to Puerto Rico," FBI Assistant Agent in Charge Steve Flores said.
Matos has multiple tattoos, including the number 1300 on the left side of his neck and the phrase "M-Town kings" on the right.
"Any kind of morsel of intelligence can really help us in locating him and taking him off the street," Flores said.
For Carvajal's sister, who spoke in front of a memorial that sits at the corner of the family's Portage Park home, the message she wants to get across to Matos is clear.
"You can run and you can continue to run for as long as you want. But you cannot hide from a higher power. Stop being a coward and give yourself up, or somebody will," Ramírez said.
The second person charged in connection with Carvajal's murder remains in federal custody awaiting trial, which is set to begin early next year.
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