Police said they were speaking with a person of interest.
Katie Kearns, 24, was found dead in her 1996 Jeep Grand Cherokee around 10 p.m. Wednesday by Will County sheriff's detectives in St. Anne, which is in a rural part of Kankakee County.
She died of a single gunshot wound to the head and her death was ruled a homicide, Kankakee County Coroner Bob Gessner said.
An autopsy was being performed Thursday and toxicology and lab results were pending, Gessner said.
A Will County Sheriff's SWAT team executed a search warrant around 10 a.m. at Outlaws Clubhouse in the 1900-block of Washington Street in nearby Joliet as part of the murder investigation, the sheriff's office said.
"SWAT vehicle, big long pole pushed door down guns drawn, it was pretty neat," said Dave Hall, a neighbor. "They towed away a white vehicle out there this morning... Besides that they've been in and out of there all day."
The towed vehicle may belong to a possible suspect.
The club for bikers is down the street from the Joliet bar where Kearns was last seen after she finished her shift as a bartender Sunday night. Confederate and American flags hang out front, and a sign on the front door says, "Is there life after death? Trespass here and find out."
Neighbors doubted Outlaws had anything to do with the Kearns murder.
"They got families, they're veterans, they actually take care of the neighborhood," said neighbor Susan Darling.
Kearns's family was devastated by the 24 year-old's death. They held a vigil outside the bar where she worked, giving her a tearful farewell.
"Tonight's not about what happened. Tonight's about the memory of my sister. It's about the memory of Katie Kearns," Matt Kearns, her brother, said.
"She lit up the room. When she was in the room, you knew it. And she didn't even have to talk," said Tim Kearns, the victim's uncle.
"She reached people. She got to people. She got to people's hearts, and she meant a lot to all of us," said Daniel Brandt, friend.
Kearns lived with her family in Mokena. Kevin Kearns had not seen or heard from his daughter in three days. He said she always stayed in touch with her family, and he was scared about what could have happened to her.
"I don't know what to think. I keep waiting for the phone call. 'Hey, Dad,'" Kearns said after she was reported missing.
Kearns was reported missing Tuesday. She was last seen around 1:30 a.m. Monday at Woody's Bar in Joliet, where she worked. Her shift had ended at midnight.
Later Monday morning, she was a no-show at her other job at Cafe Miele in nearby Orland Park. By Monday evening, when she had not returned to the home she shared with her dad and sister, the tight-knit family knew something was wrong.
"We talk all the time. We're always there for each other, so I'm scared she's not around," said Matt Kearns, her brother.
He had helped his sister get a job working with him at Barraco's Pizzeria in Orland Park. Her family said she was always a hard worker and recently took a third job at Woody's to pay for car repairs.
"She had some bills so she was trying to catch up and get things paid off," Kearns said.
Authorities said Kearns was the intended target of the shooting and there was no threat to the community.
Anyone who has information that may be pertinent to the death investigation should call the Will County Sheriff's Investigative Division at 815-727-8574 or the Will County Sheriff's dispatch center at 815-727-8575. Anonymous tips can be sent to crimestoppersofwillcounty.org.