Mom called her daughter and went to pick her up an hour later. The teen was lying on the bed with a knife in her chest.

Diana Riedell phoned her teenage daughter around 2 p.m. and an hour later went to pick her up. When Diana arrived, she found Melissa Riedell on the bed. A knife in her chest, a ligature mark around her neck.

Now, 35 years later, police have yet to make an arrest in the case.

"I wonder what it'd be like to be 55 years old, and I have a 52-year-old sister that with some kids, maybe my kids would have some cousins or I think about those kinds of things," Melissa’s brother Michael told KRDO earlier this year.

On March 7, 1986, Melissa was found dead in her apartment in Colorado Springs, Colorado. Melissa was found lying on her bed with a knife in her chest, according to the Colorado Bureau of Investigation.

Melissa was 16 years old at the time.

There did not appear to be forced entry and the door was locked when Diana arrived, according to the bureau. There were also no signs of sexual assault or a struggle.

An autopsy determined that Melissa had a ligature mark around her throat, however the ligature itself was not found. Melissa had been stabbed multiple times.

"It's kind of gory, and those are the kinds of details that just like stick in your head like, 'Oh my god, that's how it happened?'" Michael said.

Michael said his sister was a girl who just wanted to be liked but fell in with the wrong crowd when he went to college.

"She didn't look like she was 15 years old. She looked like she was you know, 20 or something, and so she had older people, an older crowd, had an older boyfriend," Michael told KRDO.

Three decades after Melissa’s murder, police continue to ask for the public’s help in finding her killer. Anyone with information is asked to contact Colorado Spring police at (719) 444-7000.