Nicole Madison Lovell
Virginia police used this photo of Nicole Lovell on missing posters when she vanished from her homeBlacksburg, Virginia, Police Department

An 18-year-old engineering student at Virginia Tech University planned for weeks to murder a shy, lonely 13-year-old girl who he wooed on a messaging site, and stashed her body in the boot of his car when he went to buy murder cleaning supplies, say investigators.

David Eisenhauer joined up with classmate Natalie Keepers, 19, to plan the murder of Nicole Lovell and together buried her body, claim detectives. They coldly discussed the plan over dinner at a fast-food restaurant in Blacksburg, Virginia, said a local prosecutor who outlined the case against them at a court hearing, CNN reported.

Eisenhauer told Keepers how he planned to lure Lovell out of her home one night, take her to a remote location and cut her throat, according to investigators. Keepers was "excited to be part of something secretive and special", the prosecutor told the judge.

They took a shovel and went to scout remote locations to hide the body, and after Lovell was killed Keepers helped Eisenhauer move her remains into the boot of his car, said the prosecutor. Her body was still in the boot while the pair went to buy cleaning supplies, he added.

Eisenhauer initially wooed Lovell on the controversial Kik app which allows anonymous messaging that law enforcement authorities have complained is increasingly being used by sexual predators.

Investigators believe that Eisenhauer lured Lovell to her death by inviting her on a late-night rendezvous. Lovell's parents discovered she had left home without their knowledge when they discovered her dresser pushed against her bedroom door and an open window she had apparently crawled through.

Lovell had brought her Minions cartoon character blanket to keep her warm. It was later recovered in Eisenhauer's home, said investigators. Her remains were found three days after she vanished 100 miles from her home.

Lovell was a lonely, sickly child bullied at school who had a liver transplant as a child and survived a battle with cancer.

"I speculate that all she was looking for was to connect with people, and she inadvertently connected with the wrong people that were looking to cause real harm and trouble," Adam Rosenberg, executive director of the Baltimore Child Abuse Center, told the Baltimore Sun.

Keepers testified at her hearing, telling the judge about her mental health struggles since the eighth grade, when she thought of suicide and began cutting herself. "I've learned ... how to love myself," Keepers said.

She is charged with being an accessory before and after the fact to a first-degree murder and with helping dispose of the body. Eisenhauer is charged with first-degree murder and abduction. They're both being held without bail.

Keepers' father, Tim Keepers, said that his daughter was a role model for her three siblings, never drank or used drugs, and grew up in a strong Christian family.

"It is still very confusing to me," he testified, referring to the crime. "We are just very, very sad."