From this Reuters story:
One current federal prosecutor learned how agents were using SOD tips after a drug agent misled him, the prosecutor told Reuters. In a Florida drug case he was handling, the prosecutor said, a DEA agent told him the investigation of a U.S. citizen began with a tip from an informant. When the prosecutor pressed for more information, he said, a DEA supervisor intervened and revealed that the tip had actually come through the SOD and from an NSA intercept.
"I was pissed," the prosecutor said. "Lying about where the information came from is a bad start if you're trying to comply with the law because it can lead to all kinds of problems with discovery and candor to the court." The prosecutor never filed charges in the case because he lost confidence in the investigation, he said.