The Impact of Forensic Evidence in Missouri Murder Convictions

The eyes of the world have been on Missouri recently—partly because of the state’s handling of forensic evidence, as well as what that evidence could or should prove. Marcellus Williams was executed for murder in Missouri state prison despite the claims of his legal team that DNA evidence had proven his actual innocence. The tragic urgency of the request makes it easy to overlook the tangle of legal standards involved.

What does forensic evidence mean to the state’s case for murder in Missouri? What can it do when a defendant is facing murder charges—or afterward?

Types of Forensic Evidence

The term “forensic” is most often applied to real evidence—physical trace evidence in a criminal case, especially the kind that requires expert testing or testimony to show its relevance. This includes:

Biological evidence, such as blood, hair, saliva, or semen
Impression evidence, including tire prints, shoe prints, and the marks of tool use
Chemical evidence, which can include drugs, accelerants, and other relevant substances
Other trace evidence, such as carpet fibers, soil or vegetation tracked inside, etc.

The Missouri State Highway Patrol, which manages forensic testing for the state, has posted its guidebook of forensic testing procedures and standards online for reference.

The Law on Forensic Evidence

In a criminal case, the state and the defense must both request that the court admit each item of evidence based on one or another of the rules—the Missouri Rules of Criminal Procedure and the laws governing evidence in Missouri (RSMo Chapter 490).

To be admissible in court, real evidence must be:

Lawfully obtained
Relevant to the case
In a clear chain of custody since its retrieval

A criminal defense attorney can attack the admission of evidence on all of these points. Even if the evidence is admitted, they can work to show the jury that the evidence does not mean what the state claims it does.

Faults in the Science

Studies have noted the presence of a “CSI effect” based on the heroic qualities of examiners and lab results in TV shows. This effect may lead jurors or members of the public to trust too much in forensic evidence or to make too much of its absence. Whether the effect favors the defense or the state—or exists at all—will depend on the circumstances of the case and the attorneys’ tactics.

Advances in research have shown that some traditional forensic science techniques are not actually reliable. For example, a recent study suggests that human bite mark analysis “lacks a sufficient scientific foundation” to identify assailants (source). Microscopic hair analysis, outside of DNA testing, has also shown serious flaws, even though some defendants have been sentenced to death on the strength of it.

According to the National Registry of Exonerations (NRE), false or misleading forensic evidence was involved in the conviction of 34% of defendants who were later exonerated of murder charges. A criminal defense attorney who is familiar with the latest scientific discoveries can challenge doubtful evidence at trial or on appeal.

Challenging the Evidence and the Police

A defense attorney’s job is to determine where the police failed and bring it to the court’s attention, as it could be a major factor in the case. The NRE also found that official misconduct led to 74% of homicide exonerations. Jonathan Irons, a Missouri man who was exonerated from assault and burglary convictions in 2020, stayed in jail for many years because of evidence that the police hid or fabricated.

In analyzing the case, the attorney will ask:

Was the arrest lawful?
Was the search lawful?
How was the search conducted?
How was the evidence collected?
Is there proof of an adequate chain of custody, showing that the evidence was properly secured?

If any of these cannot be proven, the defense can move to suppress the evidence.

Criminal Appeals

The admission of evidence is a little like a high-stakes card game. The evidence has to be admitted or denied according to the rules. And when the case is over, it is very difficult to change the outcome based on new findings. Even so, if the defense played its cards right, it is not impossible.

Criminal defendants have a right to appeal, but the appeal is limited to the facts and arguments raised at trial, with rare and difficult exceptions. If a defense attorney does not raise an issue at trial, it may not be preserved for a future appeal. An experienced criminal defense attorney understands how to work for the record on appeal as well as the trial, should the worst happen. A defense attorney can also work with new specialist counsel on the appellate filings.

A Guardian at the Courthouse Door

When a murder charge is on the table, an experienced Missouri criminal defense attorney may be the difference between life and death. As a former prosecutor, Attorney Kyle Loraine understands how the state works and how to protect defendants when the stakes are high. Call today to schedule a free 30-minute consultation at Loraine Law’s offices in Jefferson City (573-284-3048) or Kansas City 816-720-7634.

The Impact of Forensic Evidence in Missouri Murder Convictions