Police suspected Thomas Cogdell, now 18, had strangled his sister at their Camden, Arkansas home after his shock at her death stunned him into silence. Hours later, he admitted he was to blame.
During questioning following the 2006 crime, the boy - an intelligent bookworm - told police 36 times he had had no part in the killing.
But when he asked for food, officers switched off the tape recorder. Three-and-a-half hours later they switched it on again - and Cogdell confessed to the murder.
They had allegedly used tactics such as threatening him with the death penalty. He was unaware a child cannot be sentenced to such a penalty.
He eventually told police he had snapped because his sister was bossy and he put the bags over her head to teach her a lesson, The Commerical Appeal reported.But in reality, he had made up the confession, believing that DNA evidence would clear him. Read More