622 S.W.3d 321
Tex. Crim. App.2021Background
- Appellant (Carnell Petetan, Jr.) was convicted of capital murder; at the punishment phase the jury rejected his claim of intellectual disability, and the case is on direct appeal/rehearing.
- Multiple IQ tests spanning 1991–2013 produced widely divergent scores (notably: a 1992 adult test of 74; later 2012 and 2013 tests in the 50s), and several earlier tests lacked documentation about administration.
- Defense experts diagnosed mild intellectual disability or borderline functioning but some hedged their opinions; adaptive-functioning assessment relied heavily on a retrospective instrument and family informants.
- Prosecution presented evidence of malingering and deception: two psychologists doubted effort on some tests, malingering indicators were positive on later testing, and an inmate testified Petetan said he would "act mentally sick" to avoid the death penalty; the offense showed planning and manipulation.
- The dissent (Keller, P.J.) argues the jury reasonably rejected Appellant’s claim because many tests were unreliable, malingering undercut scores and adaptive-function evidence was biased and methodologically flawed; he would affirm the conviction.
Issues
| Issue | Petetan's Argument | State's Argument | Held |
|---|---|---|---|
| Burden and standard of review for ID claim | ID is an affirmative, Eighth Amendment bar to execution; Appellant met burden by preponderance | Appellant bears burden; on direct appeal factual-sufficiency review requires deference to jury | Appellant bears burden; appellate factual-sufficiency review must defer to jury unless verdict is manifestly unjust |
| Reliability of IQ testing to show deficits in general mental abilities | Multiple tests across decades consistently show scores in ID range supporting diagnosis | Many tests were unreliable or undocumented; later very low scores likely reflect malingering or poor effort; the 1992 adult test (74) was the only reliable score | Jury could reasonably discount five of six tests and rely on the 1992 adult test (74), which falls above ID range even with standard error accounted for |
| Effect of malingering/deceptive conduct on test weight | Appellant contends testing and expert assessment establish deficits | Evidence of conscious simulation (inmate’s testimony), positive malingering indices, and pattern of deception undermine reliability of low scores | Malingering and evidence of manipulation were strong reasons for the jury to discredit later low scores and some expert opinions |
| Proof of adaptive deficits | Defense experts and family informants purport to show life‑long adaptive deficits corroborating IQ results | Adaptive testing was retrospective and methodologically flawed; family witnesses had strong incentives to minimize functioning; objective records contradict many claimed deficits | Jury could reasonably reject adaptive-deficits evidence as biased or invalid; therefore finding of no ID was not manifestly unjust |
Key Cases Cited
- Moore v. Texas, 137 S. Ct. 1039 (2017) (Supreme Court guidance on using clinical standards and unreliable IQ scores in Atkins/ID determinations)
- Hall v. Florida, 572 U.S. 701 (2014) (standard-error-of-measurement and proper treatment of IQ scores under the Eighth Amendment)
- Ex parte Moore, 548 S.W.3d 552 (Tex. Crim. App. 2018) (state-court discussion of IQ-test reliability and which scores may be considered)
- Neal v. State, 256 S.W.3d 264 (Tex. Crim. App. 2008) (holding the defendant bears the burden to prove intellectual disability by a preponderance)
- Matlock v. State, 392 S.W.3d 662 (Tex. Crim. App. 2013) (describing factual‑sufficiency review standards and deference to jury findings)