The Nebraska Supreme Court on Friday upheld the convictions and death sentence of a man who killed four people in Omaha, seemingly at random, shortly after his release from prison in 2013.

Nikko Jenkins pleaded no contest in 2014 to four counts of first-degree murder and multiple weapons counts for three separate, deadly attacks around Omaha. He was sentenced to death  in 2017 after years of delays over concerns regarding his mental health. The high court’s opinion addressed combined direct appeals on Jenkins’ behalf.

Among the arguments Jenkins’ attorneys made is that the trial court abused its discretion in accepting his no-contest pleas in a death penalty case. In a no-contest plea, a defendant does not admit guilt, but concedes there is enough evidence for a conviction. The plea has the same effect as a guilty plea.

The Douglas County Public Defender office also argued that the court was wrong to allow Jenkins to represent himself and that, because it believes Jenkins is mentally ill, sentencing him to death violated the U.S. Constitution’s prohibition on cruel and unusual punishment.