Valencia, a DePaul honors student, was shot and killed while attending a Halloween party on the city's West Side.
A female partygoer was also injured in the shooting two years ago that killed Valencia.
Friday's sentencing hearing was an emotional one. Valencia's family and friends struggled to keep their composure. And, while the sentence will keep Gatica behind bars for the rest of his natural life, Valencia's family says they hope that it will serve as a deterrent for others.
"I feel numb, to be honest with you. This experience is so overwhelming. It's hard to process everything," said Joy McCormack, the victim's mother.
Ninety years in state prison is the sentence that was handed down to 21-year-old Gatica for the 2009 Halloween day murder of DePaul University student Frankie Valencia. Before the sentence was read, prosecutors brought forth Valencia's mother, his sister and the friend that was shot alongside him nearly two years ago.
All of them provided emotional and sometimes angry statements as to the profound affect Valencia's death has had on their lives.
"Nobody can force you to do something as atrocious as that," said Daisy Camacho, who survived the shooting. "I just hope that this heartbreak is not in vain and that we can see the need for prevention."
During Gatica's week-long trial last month, prosecutors said the shooting that killed Valencia happened because Gatica and other fellow gang members were upset at being kicked out of a Halloween party in Humboldt Park. Gatica, they say, procured a gun and returned to the party, opening fire on Valencia and Camacho simply because they were the ones to open the door.
The shooting was caught on surveillance tape, and Gatica confessed to police, but he later recanted that confession. His public defender Friday reacted to the sentence.
"I believe he has been wrongly convicted," said public defender Mari Jane Placek. "I feel for the family. This young man didn't deserve to die?I don't believe anyone should be murdered. I don't care if this young man --which he wasn't -- was a bad person. A bad person doesn't deserve to be killed by anyone, but nobody deserves to be wrongly convicted."
A motion to appeal the verdict and the sentence has already been filed.
Gatica is the second person sentenced in this case. The first, Berly Valladares, 21, admitted to providing Gatica with the gun and was with him when the shooting happened. He was sentenced to 70 years in prison last year.