Jeffrey MacDonald and genetic geneology

On September 2, 1997, the district court granted MacDonald's motion to file a supplemental affidavit with the Fourth Circuit Court of Appeals.[50] Lawyers representing him were given the right to pursue DNA tests on limited hair and blood evidence on October 17, 1997 by the Fourth Circuit Court of Appeals.[51] Testing began in December 2000. Defense lawyers hoped that the results would tie Stoeckley and her associate Greg Mitchell to the scene.

DNA test results released by the Armed Forces DNA Identification Laboratory on March 10, 2006, showed that neither Stoeckley's nor Mitchell's DNA matched any of the tested exhibits. A limb hair found stuck to Colette's left palm matched MacDonald's DNA profile. It also matched hairs found on the bedspread from the master bed and on the top sheet of Kristen's bed. A hair found in Colette's right palm was sourced as her own. Three hairs, one from the bedsheet, one found in her body outline in the area of her legs, and one found beneath Kristen's fingernail did not match the DNA profile of any MacDonald family member or known suspect.[52]

MacDonald was unsuccessful at incorporating a motion regarding the DNA results into his motion regarding the claims of Britt, with the court stating that he must obtain a pre-authorization for what should be a separate motion regarding the DNA results. On April 19, 2011, the U.S. Court of Appeals for the Fourth Circuit granted prefiling authorization for his DNA claim. The court reversed the district court and remanded for further proceedings.[45]

In September 2012, the District Court conducted an evidentiary hearing, including MacDonald's claims of new DNA "evidence," on remand from the Fourth Circuit's April 2011 ruling. On July 24, 2014, the District Court rejected his claims in their entirety and re-affirmed MacDonald's conviction on all counts.[46][53] He moved the district court to alter or amend the July 24, 2014 judgment, and the District Court denied his motion in November 2014. He has appealed the denial of his motion to alter or amend the July 2014 judgment to the U.S. Court of Appeals for the Fourth Circuit.[54] On December 21, 2018, in a 154-page opinion the United States Court of Appeals for the Fourth Circuit affirmed the district court's denial of relief to MacDonald.[55]

Three hairs, one from the bedsheet, one found in her body outline in the area of her legs, and one found beneath Kristen's fingernail did not match the DNA profile of any MacDonald family member or known suspect.[52]