Private First Class Matthew Zavala of the Illinois National Guard was was killed in the city's Austin neighborhood Saturday morning on the 200 block of North Lorel Avenue.
Zavala was to turn 21 next month, and friends say he had just enrolled at Harold Washington College. But it was the military that seemed a perfect career fit for Zavala, who in the end was met with violence not overseas but at home.
At the National Guard armory in Elgin, Zavala's fellow soldiers still can't believe he's gone.
"One month the guy's with you. And we're home, we're not even overseas. But yet, these things can still happen at home," said Staff Sgt. Curtis Stratton, Illinois Army National Guard.
"He would have been a stellar soldier for the rest of his career," said Sfc. Terry O'Neill, Illinois Army National Guard. "He was a phenomenal soldier, a disciplined young man. He had a bright future, a very bright future."
Flowers and candles now mark the spot where the off-duty Zavala was gunned down around 4:40 Saturday morning. Neighbors say Zavala had just exited a party bus after celebrating a friend's birthday when he was shot in the head by an unidentified gunman.
"I heard just that last shot," said Quincey Banks, witness. "When I came out I saw his body laying down on the ground, and some of his friends that were at the party, they came over and you saw them screaming."
Police say the gunman jumped in a waiting vehicle and eventually fled on foot after it crashed a block away.
It's unclear if the 20-year-old infantryman knew the person who shot him.
"That's messed up. Somebody good, somebody that's fighting for you. And it's like you're stabbing him in the back," said Daniel Robinson, victim's friend.
Private First Class Zavala had begun monthly drills in May with the first battalion, 178th infantry regiment. He had qualified as an expert marksman and aspired to fight in Afghanistan.
"I'm not going to forget that he was in our unit ever," said Sgt. Stratton. "It's a shame I'm not going to be able to be with him and maybe get deployed with him one day, and it's never going to happen."
"A motivated infantryman," said Sfc. O'Neill. "He was willing to do anything it took to get the mission done. He was solid in the field. He was a great guy to have by your side."
Zavala is survived by his mother and two siblings, including a twin brother who is also in the National Guard. Military counselors are now helping them through this difficult time.
Police have no one in custody at this time and have offered no motive for the shooting.