Inadequate legal defense also played a role in some cases of wrongful conviction.

She said she had done so after learning more about wrongful convictions in capital cases.

"The only one who benefits from a wrongful conviction is a true criminal," he added.

For that reason, the retarded face a higher risk than others of wrongful convictions, he said.

These false memories were then used as evidence in court cases leading to wrongful conviction of many people.

"I used to be bitter," he said of his own wrongful conviction.

Perhaps most important, defense lawyers are a critical safeguard against wrongful convictions.

Legal experts say wrongful convictions can and do happen elsewhere.

A wrongful conviction, of course, means that the real killer has gone free.

New York, however, is taking steps that could make wrongful convictions more likely.