In an extraordinary admission, Attorney General Eric Holder has told Congress that U.S. drone strikes since 2009 have killed four Americans — three of whom were “not specifically targeted.”

For all the effort that the Obama administration has gone to in asserting that its drones only kill the people that the administration intends to kill, Holder wrote in a letter today to Sen. Patrick Leahy (D-Vt.) that Samir Khan, 16-year-old Abdulrahman Awlaki and Jude Kenan Mohammad were “not specifically targeted by the United States.” The fourth American to die in a drone strike since 2009 was Abdulrahman’s father Anwar Awlaki, a radical propagandist whom the U.S. killed in Yemen in 2011.

The five-page letter, obtained and published by Charlie Savage of The New York Times, does not explain the circumstances that led to the unintentional killings of Khan, Mohammad and the younger Awlaki. Holder does not apologize for the killings, nor explain whether their deaths resulted from errant targeting, mistaken identity or another circumstance.

But after acknowledging that the administration did “not specifically targe[t]” those three Americans, Holder defended killing Americans the administration believes to be members of al-Qaida without due process, a constitutionally questionable proposition.

More: Holder: We’ve Droned 4 Americans, 3 by Accident. Oops.