OMAHA, Neb. (AP) — The Nebraska Supreme Court on Friday rejected the latest appeal from a man who pleaded guilty to killing his 4-year-old son but now says a discredited crime scene investigator planted evidence to frame him.

The court ruled that a Cass County judge was right to dismiss 40-year-old Ivan Henk’s post-conviction motion last year.

Henk had argued that former Douglas County CSI director Dave Kofoed planted blood evidence in a garbage bin to implicate him in the 2003 death of his son, Brendan Gonzalez. In 2010, Kofoed was convicted of evidence tampering in an unrelated murder case.

Henk argued in his post-conviction motion that without that blood evidence, he would not have admitted guilt in his son’s death and would not be serving a life sentence.

But the state Supreme Court ruled “there was ample evidence that Henk would have accepted the plea offer, regardless of the blood evidence from the dumpster.” An attorney for Henk did not immediately return a message seeking comment on the ruling Friday.

Henk pleaded guilty to first-degree murder days before his trial was to begin in October 2003 in the death of his son, avoiding a possible death sentence. The boy, who was last seen with Henk, vanished on Jan. 6, 2003. Despite an extensive, weeks-long search of the Sarpy County landfill, the little boy’s body was never found.

During a court hearing in April 2003, Henk shouted that he killed Brendan “because he was the anti-Christ. He had 666 on his forehead.” Court documents said Henk told investigators he killed the boy and threw his body in a Bellevue trash bin.

But in his appeal, Henk said that in deciding to plead guilty, he relied on DNA evidence that he now believes Kofoed planted. Henk argued that violated his right to a fair trial.

Kofoed spent nearly two years in prison for tampering with evidence in the 2008 slayings of Wayne and Sharmon Stock of rural Murdock. Kofoed claimed to have found the only physical evidence that tied two innocent men to the killings: a drop of one victim’s blood. He claimed the blood had been found in a car driven by one of the innocent men that had already been combed over by another forensic investigator.

A man and woman from Wisconsin eventually pleaded guilty to killing the couple. They’re serving life prison sentences.