When DNA evidence is presented, and allowed in at trial it is in almost all circumstances absolute, that is questionable beyond any doubt. That is the DNA tested produces a result that is so conclusive it leaves little or no doubt as to the tested results. The results are measured in the billions/trillions, meaning that out of trillions of potential matches DNA would produce a result somewhere in the range of 1 in 1,000,000.000.000 or greater showing that person is the only match out of 1 trillion+ having that DNA. Partial DNA and percentages less than 99.9999% are not conclusive and should not be used to convict a person and send that person to prison for LWOP. This is what happened to Michael Clark; his results were inconclusive. In our opinion courts should never allow inconclusive and suspicious DNA results to be presented at trial, but then again when that's all the prosecution has the courts tend to be lenient and allow these results in and typically juries buy into it.
The only piece of evidence remotely linking Michael Clark to the crime scene and the murder of Marty Grisham was a Carmex container (lip balm) found in an inconspicuous spot underneath a stairwell outside Marty Grisham’s apartment the morning after the murder.
As part of the new investigation, conducted in 2011 the Carmex container was tested for DNA and compared with Michael Clark and only Michael Clark’s DNA. At the completion of the DNA analysis of the outside of the Carmex container there was nothing else at that time that could be done further; the testing had obtained two partials but could not determine who they belonged to and they could not be linked to Mike. The interior produced an inhibited mixed sample, which when compared to Mike’s DNA matched 4 out of 16 loci, meaning Mike’s paternal lineage could not be excluded.The mixed sample, however, contained DNA from at least one other male, and could have contained DNA from more than two other males. Testing also couldn't be certain that there is no woman in the autosomal because the testing did not get a result as the contributor. When testing the inside of the Carmax container that out of the 17 potential locations, testing came up with only types at 5 of the 17 locations, a very low percentage when testing for DNA. Testing showed that because of the minor contributor that there is someone else’s DNA on that lip balm that is not Mr. Clark, and that they can't tell who that other person is. Wouldn't it have made sense to test the other potential suspects for their DNA?
No one else's DNA was compared against the sample from the Carmex container; including the other potential suspects, especially Kristen Grisham who used Carmex all the time. Nor was there any evidence presented that the DNA was run through a law enforcement database of known offenders to search for hits. Rather, the sample was tested against a database of only 4,100 people, a very low sample to come up with percentages of probability that the Y-STR DNA belonged to Mike’s paternal lineage. And DNA analysis could not say anything about when the Carmex was deposited in the hallway, nor when the DNA was deposited on the inside of the Carmex container.
Mike never used Carmex as he couldn't stand the taste or smell of it. However Kristen Grisham used Carmex all the time. If Kristen kissed Mike his DNA could have gotten on the lib palm inside that container by Kristen going into the pot rubbing it on her lower lip and then putting her finger back in the put and rubbing the balm on her upper lip.
The defense choose not to provide an expert witness to examine the questionable results presented by the prosecution's expert witness even though Mike was told an expert witness would appear on his behalf. We believe this was a mistake by defense counsel. There was much to cast doubt on, as described above and from a perception standpoint it appears more meaningful to a jury to have a defense expert witness refute the prosecution's expert witness than a defense lawyer, especially when dealing with a complex topic like DNA.
There were inconclusive results that the DNA on the Carmex container belonged to Mike. There is no evidence when or how that Carmex container was deposited at the stairwell outside Marty Gresham's apartment. None of the other potential suspects were ever tested for DNA. There could have been a female match in the mix of DNA that could have belonged to Kristen Grisham who was a frequent user of Carmex.