Ebel was due to stay in prison until 2017, his original sentence was until 2013, but in 2008 he assaulted a prison guard. For this crime, he was sentenced to an extra four years to be run "consecutively" but an error saw the word "concurrently" used instead.
The district court in Denver has issued an apology to the families of Ebel's victims, reports The Denver Post.
Ebel was killed in a bloody high speed chase in Texas on March 21, two days after Tom Clements was shot and murdered at his home and four days before the murder of pizza delivery man Nathan Leon. Ebel is believed to be responsible for both murders.
The judge who handled Ebel's second charge for assault of the prison guard failed to clarify if the charge was to run "consecutively", which led officials to add the four year sentence to Ebel's prison time "concurrently." This means for the assault, Ebel received no extra time in prison.
The statement from District Administrator Walter Blair said:
Because the judge did not expressly state that the sentence was consecutive, the court judicial assistant did not include that term in the mittimus, the sentence order that went to the Department of Corrections, the court regrets this oversight and extends condolences to the families of Mr. Nathan Leon and Mr. Tom Clements.
But prosecutor, Bryan L. Hunt, who tried Ebel's second charge maintains he was seeking a "consecutive" sentence:
The deal I made is it was consecutive, Is there any way it could be automatically changed without me being involved? I don't know of any. Any changes for good behavior reduction would be the jurisdiction of DOC, not me. Once somebody is committed to the DOC, then the exact aspects of the sentence are in the jurisdiction of the DOC.
Last week a woman was arrested for allegedly buying the gun that killed Tom Clements.