Couey was convicted of breaking into the home of Jessica's grandparents, where she lived with her father, abducting her from her bedroom, taking her to the mobile home where he lived, concealing her in a closet, raping her and finally burying her alive in trash bags in the backyard.
"A person who is mentally retarded simply could not have planned such a sophisticated crime, and escape," Judge Ric Howard wrote.
Couey's attorneys argued that he suffered lifelong mental abuse and had an IQ below 70. Judge Howard ruled that the most credible exam rated Couey's IQ at 78, above the level considered retarded in Florida.
The U.S. Supreme Court has ruled that mentally retarded persons can not be executed. Couey's jury voted 10-2 in favor of the death penalty, but the final decision is up to Judge Howard.