In the midst of a fiery floor debate over contempt proceedings for Attorney General Eric Holder, House Oversight and Government Reform Chairman Darrell Issa (R-Calif.) quietly dropped a bombshell letter into the Congressional Record.

The May 24 letter to Rep. Elijah Cummings (D-Md.), ranking member on the panel, quotes from and describes in detail a secret wiretap application that has become a point of debate in the GOP’s “Fast and Furious” gun-walking probe.

The wiretap applications are under court seal, and releasing such information to the public would ordinarily be illegal. But Issa appears to be protected by the Speech or Debate Clause in the Constitution, which offers immunity for Congressional speech, especially on a chamber’s floor.

According to the letter, the wiretap applications contained a startling amount of detail about the operation, which would have tipped off anyone who read them closely about what tactics were being used.

Holder and Cummings have both maintained that the wiretap applications did not contain such details and that the applications were reviewed narrowly for probable cause, not for whether any investigatory tactics contained followed Justice Department policy.