Natasha Wallen Cornett was born on January 26, 1979, in Betsy Layne, Kentucky. She was born into a poor family in rural Pike County. Her mother, Madonna Wallen, had a complicated relationship with Natasha's biological father, who was a local policeman named Roger Burgess. Madonna was not married to Roger when Natasha was born. When Natasha was just a toddler, her mother left her husband, Ed Wallen, and chose to raise Natasha alone in a trailer on the outskirts of Pikeville, Kentucky.

Growing up, Natasha did not receive much support from either her biological father or from Ed Wallen, who was listed on her birth certificate. Reports describe her childhood as lacking a father figure and having an irresponsible mother. By the time she reached junior high school, Natasha felt isolated from her classmates. Her behavior was considered unconventional, and she struggled with anorexia and bipolar disorder. Unfortunately, her mental health issues went largely untreated because her family could not afford health insurance.

As Natasha entered high school, the bullying and harassment from her peers increased due to her unique style and conduct. She felt ignored and unsupported by school authorities despite her pleas for help. In her freshman year, Natasha dropped out of school.

On her 17th birthday, Natasha married a long-time friend, Stephen Cornett. However, the marriage only lasted about six months, which led to deep emotional distress for Natasha. This failure added to her existing mental health challenges.

By the time of her marriage, Natasha had fully embraced the Goth subculture. She wore black clothing, listened to dark music, and showed interest in the occult. During this time, she also struggled with substance abuse, including drugs and alcohol. She began to self-harm and became the leader of a group of young people who shared similar interests and struggles.

On April 6, 1997, Natasha Wallen Cornett, along with five friends, was traveling in search of a new life. They came across the Lillelid family at a rest area in Tennessee. The Lillelid family included Vidar, Delfina, and their two children, Tabitha and Peter. Cornett and her friends had plans to steal the family's van. They forced the Lillelids back into their vehicle at gunpoint with the intention of driving them to a secluded area.

Once they arrived at a deserted road in Baileyton, the family was shot execution-style. The young Jason Bryant, aged 14, was reportedly the one who actually pulled the trigger. The group then abandoned their own vehicle and left in the Lillelid family's van. Vidar and Delfina were found dead at the scene, while Tabitha succumbed to her injuries in the hospital. Young Peter survived but was left blind in one eye and permanently disabled.

Just two days after the murders, the group was apprehended by U.S. Customs and Immigration officials in Arizona. They had attempted to enter Mexico without proper documentation. Following their arrest, they were taken to Greeneville, Tennessee, where they faced charges of first-degree murder, attempted murder, and kidnapping.

During the trial, Cornett accepted legal representation from an attorney who did not specialize in criminal defense. Under his guidance, she made controversial statements about being involved in satanic worship. The judge decided to replace her attorney before the trial proceeded. The district attorney offered a plea deal to all defendants: plead guilty to avoid the risk of the death penalty. On March 13, 1998, Cornett and her co-defendants pleaded guilty. Although she did not fire the weapon, she received three life sentences without the possibility of parole and two additional sentences of 25 years for attempted murder and kidnapping.

In prison, Cornett worked on her education and gained her cosmetology certification. In 2001, she was involved in an incident where another inmate was nearly strangled, but there wasn't enough evidence to charge her with a crime.