Nelson pleaded guilty to the charges pertaining to the murder of Butler and he was sentenced to death by a federal jury in November 2001.

[1] On October 12, 1999, 24-year-old Keith Dwayne Nelson planned to kidnap, rape, and murder a young girl in the Kansas City area.

[2][3] Nelson drove for a distance before he reached Grain Valley, Missouri, where he raped Butler in a forest before he used a piece of wire to strangle her to death.

[2][4] Butler's family and friends were reportedly devastated over her death, and many remembered her fondly as a straight-A student and sweet girl.

[8] Born on November 23, 1974, Keith Dwayne Nelson, who had a twin brother and three more siblings, grew up in Texas, before he moved to Missouri.

Nelson was reportedly diagnosed with dyslexia and did not fare well in his schooling years, often getting into fights or having behavioral problems, and was not academically inclined.

Prior to murdering Butler, Nelson was previously convicted of lesser offenses, three times for theft (all in Missouri) and once for attempting to escape custody.

[2] On September 29, 1999, Nelson allegedly told a co-worker that he wanted to kidnap, rape, and kill a woman, stating that it would not make a difference since he would be back in prison for another offense.

He attempted to carry out this plan on October 2, 1999, when he held a knife to the throat of Michanne Mattson, a medical student, and tried to force her into his vehicle but she managed to escape.

[2] The trial was postponed at one point after Nelson was hospitalized for undisclosed reasons,[13] which was later revealed to be a suicide attempt by an anti-depressant pill overdose.

[2] In rebuttal, the prosecution argued that Nelson's troubled childhood and other sympathetic circumstances of his life were not an excuse for his heinous actions of raping and murdering a young girl of Butler's age.

They added that Nelson's case was undeserving of any ounce of mercy for he had cruelly murdered Butler in cold blood and deprived her of both her dignity and right to life.

Additionally, they added he should be wholly responsible for his barbaric choices of committing a murder in the most horrific way possible to a child no matter how bad his upbringing, since his character was "rotten to the core".

[16] In accordance to the jury's verdict, Justice Fernando J. Gaitan sentenced 27-year-old Keith Dwayne Nelson to death by lethal injection during an official hearing convened on March 11, 2002.

[28] They also argued that Nelson was denied access to any effective trial counsel and the jury sentenced him to death back in 2001 without thorough hearing of the mitigating circumstances in his case, including the possibility of brain damage caused by premature birth, mental illness, and both physical and sexual abuse as a child.

[31][32] On August 28, 2020, 45-year-old Keith Dwayne Nelson was officially put to death by lethal injection at the USP Terre Haute.

"[37] According to Christopher Vialva, another federal death row inmate, Nelson talked a lot in the final two days of his life.

[44][45][46] A year after Nelson died, Sister Barbara Battista, a Roman Catholic nun who was a staunch opponent of the death penalty, stated that she chose to accompany Nelson and offered him prayers in the execution chamber during the final minutes of his life, as she believed that no matter her feelings towards capital punishment or how heinous the actions of the killer were, she felt that every person on the verge of execution deserved the right of having someone's accompaniment and provide them spiritual support.