Hall County teenagers are in shock to learn their friend and popular classmate, Hannah Truelove, was killed.

Investigators with the Hall County Sheriff's Office said they have opened a homicide investigation into her death.

Channel 2's Linda Stouffer asked investigators Monday whether this was a random crime

"We think at this point it's not a random crime. We think that this was a crime that involved persons who knew each other. We have no indication it was random," Maj. Woodrow Tripp of the Hall County Sheriff's Office said.

However, they are not ready to release more details from the GBI autopsy on the 16-year-old.

Tripp would only describe her death as "violent."

Jan Tollison, Truelove's aunt, told Channel 2's Carol Sbarge that it is awful not knowing what happened to the teen.

"I can't keep saying it enough. We want answers. We want to know why, we want to know who thought it was OK to do this to her. We want him behind bars," Tollison said.

Tripp said witnesses remember seeing Truelove Thursday evening near the Lanier Club Apartments.

There was someone else with her but Tripp declined to say whether it was a man or a woman.

"We are looking at several different persons of interest. We have several different side investigations going on," Tripp said.

Truelove was a student at Gainesville High School where counselors were on hand for anyone who needed help Monday.

Superintendent Merrianne Dyer said if students can help provide information in the homicide investigation, they are asked to contact the Hall County Sheriff's Office.

Truelove's Twitter page referenced a "stalker"on Aug. 12.

Tripp said although they are looking at social media posts, it might not be connected, as a teenager's interpretation of a stalker could be different than an adult's.

A large rock down the street from the school is now covered in paint that says "Hearts for Hannah," and "RIP."

People have been pouring out their condolences on Twitter as well, using a #heartsforhannah hashtag.

One person also tweeted: "sick world."

"Not just for the family -- but for all her friends -- we're all suffering; we want to know what happened to her," Tollison said.