A court overturned the conviction of Andrea Yates, the Texas mother who drowned her five children in 2002. Why? Because the her defense team successfully showed that a prosecution witness gave false testimony:
The Texas First Court of Appeals ruled that the conviction should be reversed because an expert witness for the state, Dr. Park Dietz, presented false testimony when he said Yates may have been influenced by an episode of the "Law & Order" television program. No such episode had ever aired.
Yates, now 40, apparently was a fan of the show and watched regularly.
Hello! The imagined episode was one where a woman was "found innocent by reason of insanity for drowning her children"; it also turns out that Dr. Dietz had been a consultant on the show. When the defense contacted the producers, the truth was discovered. This must be a first: Using a TV program to get a woman convicted, only to later realize the TV program never existed! The prosecution can still ask a higher court to reverse this ruling.
While it's not the most comprehensive, if you do a simple "Find" search on the Law & Order episode guide at TV Tome, no "drownings" appear. And the Washington Post looked at how Law & Order makes it hard for convictions, way back in 2003.
