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Bebeto Matthews, File, Associated Press
In this May 6, 2014 file photo, Robert Hill, center, stands with his lawyers Harold Ferguson, left, and Sharon Katz, right, as Justice Neil Firetog declares Hill exonerated in Brooklyn Supreme Court, in the Brooklyn borough of New York.

NEW YORK — When three half brothers' decades-old murder convictions were thrown out last month, they became a dramatic example of an idea spreading among prosecutors nationwide: "integrity units" dedicated to double-checking convictions.

Over the last seven years, more than a dozen prosecutors' offices have created such staff teams or expert panels to review wrongful-conviction claims. The groups have agreed to take second looks at more than 4,900 cases, resulting in at least 61 convictions tossed so far.

That's according to a tally compiled from interviews, prosecutors' reports and news accounts.

The initiatives are underway from New York City to Santa Clara County, California, and from Chicago to Dallas.

Advocates see the reviews as open-minded efforts to address possible injustice. But some defense attorneys are cautious about embracing them.