The government published its latest Wiretap Report on July 1. The headline finding was that encryption wasn't foiling federal and state law enforcement officials, despite a growing chorus of people suggesting that we're all gonna die unless the tech sector builds backdoor access into their products to enable government access.

In all, the federal agency that oversees the courts reported to Congress that there were 3,554 wiretaps in 2014, about 1 percent less than the year prior. Of the total, only four were thwarted via encryption.

But the reported number of wiretaps by the Administrative Office of the US Courts (AO) simply doesn't add up. That's according to Albert Gidari, one of the nation's top privacy lawyers. He says "there is a bigger story" that calls into question the AO's accounting:

Since the Snowden revelations, more and more companies have started publishing “transparency reports” about the number and nature of government demands to access their users’ data. AT&T, Verizon, and Sprint published data for 2014 earlier this year and T-Mobile published its first transparency report on the same day the AO released the Wiretap Report. In aggregate, the four companies state that they implemented 10,712 wiretaps, a threefold difference over the total number reported by the AO. Note that the 10,712 number is only for the four companies listed above and does not reflect wiretap orders received by other telephone carriers or online providers, so the discrepancy actually is larger.

How can that be? Even taking into account some accounting complexities, Gidari says, "the numbers are still off by more than twofold" in one scenario.

"Are wiretaps being consistently under­reported to Congress and the public?" he asks. "Based on the data reported by the four major carriers for 2013 and 2014, it certainly would appear to be the case." In an e-mail to Ars, he said "we are still off by 30 percent" even if "all four carriers got the same order and it covered multiple devices."

Charles Hall, an AO spokesman, told Ars in an e-mail that the agency was investigating the discrepancy.