Supreme Court Defines Parameters for Expert Testimony Surrounding Intellectual Disability in Death Penalty Cases

April 11, 2011

The Tennessee Supreme Court today ruled that expert testimony may be considered when determining whether a person facing the death penalty is intellectually disabled. Under Tennessee law, persons with intellectual disability (formerly referred to as “mental retardation”) cannot be executed.

In the post-conviction appeal of death-row inmate Michael Angelo Coleman, the Court found that state law does not require I.Q. scores to be accepted at their “face value”. Instead, the courts may consider expert testimony to determine whether the score accurately reflects the defendant’s functional I.Q. The Supreme Court remanded Mr. Coleman’s case to the trial court for further proceedings to determine if he meets the definition of intellectual disability.

In order for a person to be found to be intellectually disabled, the Tennessee statute requires a functional intelligence quotient of seventy (70) or below and deficits in adaptive behavior. Additionally, the intellectual disability must have been manifested before the age of 18. However, the Court pointed out that the law does not articulate the types of evidence that may be considered.

“While a person’s I.Q. is customarily obtained using standardized intelligence tests…the statute does not provide clear direction regarding how a person’s I.Q. should be determined and does not specify any particular test or testing method that should be used,” Justice William C. Koch, Jr. wrote for the Supreme Court.

Mr. Coleman was convicted of the 1979 murder committed during the robbery of a Memphis man on his way to the grocery store.

In his post-conviction appeal, Mr. Coleman argued that the post-conviction trial court and Court of Criminal Appeals incorrectly concluded that he did not meet the statutory definition of intellectually disabled.

In today’s unanimous ruling, the Supreme Court found the lower courts erred by failing to consider the testimony of two expert witnesses indicating Mr. Coleman is intellectually disabled. The Court also determined the lower courts incorrectly treated Mr. Coleman’s intellectual disability and mental illness as two separate causes of his adaptive limitations.

Upon remand, the State, which did not present any counter testimony at the post-conviction hearing, may challenge the admissibility of the expert testimony and present testimony to counter the methods of Mr. Coleman’s expert witnesses.

In his post-conviction appeal, Mr. Coleman also argued that he received ineffective counsel during his trial because his attorney failed to investigate or present mitigating evidence. However, the Supreme Court agreed with the lower courts that Mr. Coleman’s ineffective counsel claims are procedurally barred because his motion to re-open his post-conviction petition falls outside of the statute of limitations and his claim does not satisfy one of the exceptions outlined in the statute.

Download Opinion - Michael Angelo Coleman v. State of Tennessee