SPRINGFIELD, Mo. (AP) — A southwestern Missouri man who spent eight years behind bars for his wife’s death before being exonerated is suing the detective who helped convict him.

Lisa Jennings’ Christmas Day death in 2006 was initially ruled a suicide.

She had been shot at her Buffalo home.

But an investigation led by Missouri State Highway Patrol detective Dan Nash determined that hand blood spatters were inconsistent with suicide.

Brad Jennings was convicted of first-degree murder in 2009.

A judge ordered him released in February because authorities failed to disclose that the robe he was wearing at the time of his wife’s death tested negative for gunshot residue.

Jennings’ federal lawsuit accuses Nash of civil rights violations, the Springfield News-Leader reported.

The Missouri Attorney General’s office, which is representing Nash, declined comment.

The suit said Nash misrepresented himself as a blood spatter expert.

The News-Leader reported that Nash had no formal blood spatter training at the time he conducted the investigation, though he completed a week-long course about a year after the trial.

Prosecutors said at trial that Jennings, 62, who did not testify, killed his wife while wearing the bathrobe, but changed clothes and washed up to remove gunshot residue from his hands before police arrived. Gunshot residue tests on his hands were negative.

The prosecutor also suggested that the reason Lisa Jennings had gunshot residue on her right hand wasn’t because she fired the weapon, but because she was near Brad Jennings when he fired it.

Nash said during Jennings’ trial the he had investigated about 300 deaths, and in at least half of the cases, he used blood spatter analysis.

He has continued to investigate deaths in the decade since.

The News-Leader submitted a records request for investigative reports written by Nash about blood spatter analysis in the past decade.

The patrol assigned the request to Nash, calling him the most qualified to retrieve the records.

Two months after the records request and at a cost of more than $700, the patrol turned over two reports comprising 11 pages.

Before Attorney General Josh Hawley decided not to retry Jennings for murder this summer, his office hired a Kansas forensics company to independently review the case.

The independent review ruled the blood spatter evidence in the Jennings case was inconclusive in determining if the death was homicide or suicide.