New research shows how people who were apparently uninvolved in a crime could provide such a detailed account of what occurred, allowing prosecutors to claim that only the defendant could have committed the crime.

An article by Professor Garrett draws on trial transcripts, recorded confessions and other background materials to show how incriminating facts got into those confessions — by police introducing important facts about the case, whether intentionally or unintentionally, during the interrogation.

To defense lawyers, the new research is eye opening. “In the past, if somebody confessed, that was the end,” said Peter J. Neufeld, a founder of the Innocence Project, an organization based in Manhattan. “You couldn’t imagine going forward.”

The notion that such detailed confessions might be deemed voluntary because the defendants were not beaten or coerced suggests that courts should not simply look at whether confessions are voluntary, Mr. Neufeld said. “They should look at whether they are reliable.”