Tori Lang, 18, was found dead in Yellow River Park in Stone Mountain, Ga., on July 28


Tori Lang had everything to look forward to.  

The 18-year-old Stephenson High School honors graduate was enrolled in an electrical apprenticeship program with a plan to attend college. She loved her Pomeranian dog, Tyga, and was delivering groceries part-time.

In her free time, she loved coming up with inventions with her dad Torrey, an inventor and former truck driver.

"We got vision boards all around the house," says Torrey. "We would share ideas. I needed her brain so I'd be in tune with things. She'd say, 'Oh, Daddy, you use this, kids are not doing that anymore.' She kept me innovative."

Then, tragedy struck.

On July 28, a passerby found her body in Yellow River Park in Stone Mountain, Ga. She had been killed by a gunshot wound.

Tori Labg
Tori Lang
| Credit: GoFundMe
tori lang family
Tori Lang and her parents Teresa and Torrey
| Credit: Courtesy Lang Family

Several days later, her 2012 Nissan Versa was discovered about four miles away in Hidden Acres Nature Preserve. It had been torched.

Police believe the killer abandoned her car.

"That would be the natural thought," Gwinnett County Police Sgt. Jennifer Richter tells PEOPLE. "I don't know how it would get there otherwise."

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Although a motive is unclear, police have ruled out robbery.

"There is no indication that it was a robbery," says Richter.

Tori's family won't stop until they get answers.

"Someone needs to answer for what they did to our child," says Tori's aunt, Tamara Lang, in this week's issue of PEOPLE. "We want justice. We won't stop until we get it."

Torrey believes that some of Tori's friends know more about what happened than they're letting on.

 "They're not talking," he says. "It's radio silence. You can't get in touch with them." 

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On the day of her disappearance, Tori drove away from her family home in Lithonia without letting her parents know where she was headed.

Her last known sighting was on a surveillance video taken at about 10:30 p.m. on July 27. In the video, Tori is seen checking the family mailbox at their home before disappearing.

Her body was found the following day under a tree.

Police say they have multiple suspects.

"[Detectives] aren't ready to put anything out about any particular person and they haven't really ruled anybody out yet either," says Richter.

Investigators are "still looking for anybody that has information," she says. "Anything to pass on call us."

Meanwhile, Tori's family has set up a GoFundMe page asking for "anyone with information on the shooter to PLEASE come forth."

"You can remain anonymous," it reads.

Anyone with information about the shooting is asked to contact Crime Stoppers at 404-577-8477 or Gwinnett County Police Investigations at 770-513-5300.