It’s been almost exactly a year since Aaren O’Connor was killed by a stray bullet as she sat in her car in the Heart of Chicago neighborhood on her phone, talking to her family back in her native Southern California.

No arrests have been made in the months since, and on Tuesday, Chicago police held a news conference to make a plea for help to the public to bring her killer to justice.

Lt. Osvaldo Valdez, who is supervising the investigation, said detectives believe a reputed gang member killed O’Connor while aiming at rivals in another vehicle. The suspect was interviewed by investigators, but authorities lack enough evidence to bring murder charges, he said.

"Unfortunately, as how the criminal justice system is set up, it’s not what we think or what we theorize or what we believe, it’s what we can prove," Valdez told reporters at Area Central police headquarters on the South Side. "We need witnesses."

O’Connor was fatally shot Feb. 5, 2016, a year that ended for Chicago with more than 760 homicides, the most in two decades.

The 25-year-old was found struck in the head around 7:30 p.m. as she sat in her car in the 2000 block of 21st Street, a few doors down from where she lived. She was talking on the phone with her sister in San Diego when O’Connor suddenly started sounding incoherent, according to Valdez. Her sister then passed the phone to their father, David O’Connor.

"She was having trouble speaking," he told the Tribune last year. "She didn’t know where she was. She kept saying her head hurts, her head hurts. I thought maybe she was having a stroke or something."

Reward offered in chicago woman’s killing

Aaren O’Connor was shot in the head while sitting outside her Pilsen apartment last week. Feb. 12, 2016. (CBS Chicago)

Aaren O’Connor was shot in the head while sitting outside her Pilsen apartment last week. Feb. 12, 2016. (CBS Chicago)

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The family got in touch with O’Connor’s boyfriend, who called her roommate. She went outside and found O’Connor in the car .

O’Connor was later pronounced dead at a local hospital.

On Tuesday, Valdez said the gunman fired at least three gunshots at rival gang members he believed were in a vehicle. Valdez said three or four gang members were hanging out on a nearby corner around the time of the shooting.

Valdez described O’Connor as "a talented and bright, beautiful young lady" who graduated from college and traveled abroad to Japan. Valdez said she also learned a couple of different languages, including Korean.

"As a father myself, it touched my heart to go out and investigate and canvass and work with the detectives," Valdez said. "I couldn’t help but think this is just another life that is taken, an innocent life that is taken, because of gang crime activity."

Valdez urged anyone with any information about the case to call Area Central homicide detectives at 312-747-8380.

Father of woman, 25, killed by stray bullet recounts final conversation with her

David O’Connor says he didn’t realize he was speaking to his 25-year-old daughter, Aaren, for the last time when he spoke to her on the phone just after she was shot in the head by a stray bullet in the Heart of Chicago neighborhood. Feb. 8, 2016. (CBS Chicago)

David O’Connor says he didn’t realize he was speaking to his 25-year-old daughter, Aaren, for the last time when he spoke to her on the phone just after she was shot in the head by a stray bullet in the Heart of Chicago neighborhood. Feb. 8, 2016. (CBS Chicago)

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"To put it in sports terms, we’re in the red zone with this case," he said. "We just need a little bit more help from the community."

jgorner@chicagotribune.com

Twitter @JeremyGorner

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