How Are Bloodstain Pattern Opinions Evaluated?
Stains on a wall can show some things about how blood landed. They can’t tell the whole story of a fight.
Mr. Heath Enix 'Heath' Hyde
Attorney at Law · Eligible to Practice in Texas
Bar Card Number: 00796807
TX License Date: 11/01/1996
Primary Practice Location: Sulphur Springs, TX and Dallas, TX
Office Address: 214 Connally St Ste A
Sulphur Spgs, TX 75482-2612
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Short answer
Start with the photos and the analyst’s notes. Measurements of drop size and angle rest on physics; a claim about who stood where may not. Your lawyer separates the two and challenges the leap.
| What the State may say | What the defense checks |
|---|---|
| “The spatter shows he was standing over her.” | It checks whether the pattern supports a position or only a general area. |
| “Blood on his shirt proves he was there during the beating.” | It checks whether contact after the event could explain the stain. |
| “The blood was cleaned up.” | It checks how the presumptive test was run and whether anything confirmed it was blood. |
| “Our analyst has done this for twenty years.” | Experience doesn’t replace a method that the analyst can explain and support. |
What can bloodstain pattern analysis show?
A 2009 National Research Council report found that science supports some parts of bloodstain analysis better than others.
| Type of conclusion | How the report described it |
|---|---|
| Whether blood spattered quickly or slowly | The report said scientific studies support this kind of conclusion. |
| How a complex event unfolded | The report warned that some experts extrapolate far beyond what the science supports. |
| Patterns from gunshot wounds in soft tissue | The report said these patterns are highly variable. |
| Overall reliability of opinions | The report called analysts’ opinions more subjective than scientific and the uncertainties enormous. |
The same report flagged a training gap.
| Issue in the report | Why it matters in your case |
|---|---|
| The IAI’s bloodstain certification has no educational requirement. | The defense can ask about the analyst’s science background, not just hours of training. |
| Many requests come from one side with targeted questions. | That setup can create context bias, so the defense asks what the analyst was told first. |
| Overlapping patterns can be harder to read than they look. | A single photo may not show which stain came first. |
What records should the defense get?
A bloodstain opinion is only as good as the documentation behind it.
| Record | Reason |
|---|---|
| Every scene photo, with scales and the photo log | Any measurement the analyst reports should trace back to a photo or note. |
| The analyst’s notes, sketches, and any string or software reconstruction | They show the measurements and the assumptions. |
| Presumptive and confirmatory blood test results | Some red substances aren’t blood, and some blood isn’t red. |
| DNA results on key stains | The pattern doesn’t say whose blood it is. |
| Information the analyst received before reviewing the scene | It shows whether the investigators’ theory shaped the review. |
| Clothing and items, preserved for inspection | A defense expert may need to examine the items, not just the pictures. |
How does the defense challenge a bloodstain opinion in court?
Texas law gives the defense several tools before and during trial.
| Rule or law | What it lets the defense do |
|---|---|
| TRE 702 | The defense can challenge the analyst’s qualifications and whether the opinion will help the jury. |
| TRE 705(b) | In a criminal case, the defense must be allowed to question the analyst about the underlying data outside the jury’s hearing. |
| TRE 705(c) | The defense can object that the underlying facts or data don’t provide a sufficient basis for the opinion. |
| CCP art. 39.14(b) | A written request made by the 30th day before jury selection requires the State to name its experts by the 20th day before. |
| CCP art. 39.14(h) | The State must disclose favorable information, including any opinion that cuts against its theory. |
Accreditation and licensing rules may also apply.
| Texas law | The question to ask |
|---|---|
| CCP art. 38.35(d) | A forensic analysis from a lab the Texas Forensic Science Commission hadn’t accredited is inadmissible, unless an exception applies. Ask whether this bloodstain work counts as forensic analysis under the commission’s rules. |
| CCP art. 38.01, Sec. 4-a | A forensic analyst at an accredited lab needs a license. Ask whether the analyst holds one. |
| CCP art. 38.01, Sec. 4(a)(3) | The Texas Forensic Science Commission can look into a complaint that sloppy work changed a result or testimony. |
How does bloodstain evidence fit the rest of the case?
A pattern can matter most when the question is how a struggle happened, not who was there.
| Hypothetical | Why it matters |
|---|---|
| The defendant says the other man attacked first. | Stain locations may support or undercut a self-defense account. |
| The defendant tried to help the injured person. | Contact stains on clothing can come from first aid. |
| The State’s theory is a planned killing. | The pattern may say little about intent. |
| Paramedics moved the body before photos were taken. | Later activity can create new stains at the scene. |
Frequently asked questions
| Question | Answer |
|---|---|
| Is bloodstain pattern analysis considered reliable? | The 2009 National Research Council report said some parts rest on solid science and others don’t. The judge decides admissibility under Rule 702 in each case. |
| Can the defense hire its own bloodstain expert? | That’s a decision for the defense lawyer. An independent analyst can review the photos and the State’s method before trial. |
| What if a conviction relied on bloodstain testimony that’s now doubted? | CCP art. 11.073 allows habeas relief based on new scientific evidence in certain cases, including evidence that contradicts science the State relied on at trial. |
Talk with Heath Hyde
Ask early for the analyst’s photos and notes. Call Heath Hyde, P.C. at 903.439.0000 or request a free consultation.
Legal sources
- Tex. R. Evid. 702–705
- Tex. Code Crim. Proc. arts. 38.01, 38.35
- Tex. Code Crim. Proc. art. 39.14
- Tex. Code Crim. Proc. art. 11.073
This article provides general educational information, not legal advice. Every case depends on its facts, evidence, court, deadlines and governing law. Past results do not guarantee a similar outcome.
