Ooops

Well, the conspiracy theorists who believe that Dallas is the sacred cow this year that the NFL wants them to be in the Super bowl will have a lot to talk about.
From ESPN: NFL head of officials Dean Blandino said Monday that the non-call on pass interference against Detroit Lions tight end Brandon Pettigrew by Dallas Cowboys linebacker Anthony Hitchens was debatable, but holding definitely should have been called on the play.
Blandino, speaking on NBC Sports Radio's "Pro Football Talk Live," said the officiating crew erred by announcing a penalty and then picking up the flag. Ideally, he said, the crew would have discussed the play and then announced that there was no penalty on the play. If the crew had handled the situation in this manner, "it would have mitigated some of the response to this," he said.
Blandino said that when he reviewed the play, it appeared as a "judgment call that could have gone either way." But he saw a clear "jersey grab" by Hitchens that should have resulted in a defensive holding call that "should have been called."
The 5-yard defensive holding call would have given the Lions a first down, as the play came on a Matthew Stafford pass on third-and-1 from the Dallas 46. The Lions lined up on fourth down but eventually punted after failing to draw the Cowboys offside. Dallas scored the eventual winning points in the 24-20 wild-card win on the ensuing drive.  http://espn.go.com/dallas/nfl/story/_/id/12124549/dean-blandino-holding-call-missed-vs-dallas-cowboys-lb-anthony-hitchens
Of course, the "call" is not the only reason why Detroit lost, but it was a crucial and a turning point play.
I think the NFL referees are the most honest referees/umpires out there in professional sports, so I doubt that there was a conspiracy, but this has to rank in the top 10 blown calls of all time in the NFL.