Frye/Mack Challenge to Admissibility of Gunshot Residue Evidence Fails.

State v. Loving, Minn.S.Ct., 12/167/2009.  A jury convicted Mr. Allen of the premeditated murders of Mr. Allen and Ms. Peters.  Mr. Loving and Ms. Peters had been in a relationship that was often abusive.  Mr. Allen was Ms. Peters’ current boyfriend at the time of the murders.

A forensics expert tested the clothing that the police believed that Mr. Loving had been wearing during the shootings for the presence of gunshot residue.  Using something called SEM/EDX, the expert found three-element particles of gunshot residue on a coat, and two-element particles consistent with gunshot residue on a pair of pants, a glove, and elsewhere on the coat.  The trial court held a Frye-Mack hearing on the admissibility of the gunshot residue evidence, after which it admitted the three-element particles evidence but not the two-elements evidence.

Mr. Loving conceded that gunshot residue testing with this SEM/EDX is generally accepted in the relevant scientific community.  His complaint, rather, was that:

there is no way to determine how or when GSR lands on clothing because GSR can be transferred in a number of ways, does not disintegrate, and can remain on clothing even after washing. Essentially, Loving asserts that the test’s inability to determine how or when GSR got on the clothing indicates that the meaning of the test is unreliable.

The appellate court says, no, this is about the weight of the evidence, not the reliability of it.  That there are multiple possibilities of how or when gunshot residue got transferred to the coat did not make SEM/EDX analysis or the gunshot residue evidence unreliable.  The appellate court also rejected an argument that this evidence was not helpful under the rules of evidence because of these multiple possibilities (and others as well). 

Finally, Mr. Loving complained about the admission of relationship evidence, introduced under Rule 404(b), arguing that it’s probative value was outweighed by its potential for unfair prejudice.  The appellate court found no error in admitting this evidence.