One in 25 Inmates Sentenced to Death In the U.S. Might Be Innocent: Study

One in 25 inmates sentenced to death in U.S. prisons are probably innocent, according to a new study published by the Proceedings magazine of the National Academy of Sciences.

The unexpected result has added a new element to the debate on the death penalty in the U.S., since the number of people who might have been executed unjustly is a hard question to answer.

According to Reuters, the study estimates that in the last three decades, at least 300 people sentenced to death were innocent.

Although during this time many inmates have been exonerated due to the advances of science and law, the new study concludes that it's possible that a high amount of people were declared guilty incorrectly.

"Our investigation joins the alarming news that most innocent people sentenced to death have not been exonerated," said Professor Samuel Gross of the University of Michigan, main author of the study.

The research looked into the situation of 7,482 inmates sentenced to death between January 1974 and December 2004, of which 12.6% were executed, while only 1.6% were exonerated and set free, highlighted The Guardian.

So, the study estimates that between 1974 and 2004, close to 340 inmates were executed in comparison to the 138 proven innocent.

"This is a disturbing find. There's a large number of people who are sentenced to death and despite our best efforts some of them, without a doubt, have been executed," said Professor Gross.

The study found that one of the main causes for innocent inmates not being identified is because in most cases, 61%, they are sentenced to live in prison, and once this happens their cases stop being revised, and a great number of innocent people spend the rest of their lives behind bars.