Washington Post writer Elizabeth Flock has resigned after an editor's note appeared for the second time in four months atop a Washington Post story by her. She resigned on Friday. "I enjoyed aspects of working on Blogpost, particularly online reporting," Flock writes in an email. "But I've always sought a pure reporting position over one that involves aggregation. And I believe the best avenue for this is outside the Washington Post."

In a follow-up phone call, Flock said, "I was in no way pressured to resign. There was no indication I was going to be fired. There was no talk of anything that major. It was purely my decision."

The latest note says material was taken improperly from another source:

EDITORS' NOTE: An earlier version of this report made inappropriate, extensive use of an original report by Discovery News and also failed to credit that news organization as the primary source for the blog post. This was a significant ethical lapse and not in keeping with our journalistic standards. We apologize to Discovery News.

Flock also drew an editor's note for a piece last December about Mitt Romney and a KKK slogan. That one drew an ombudsman column, too.

I can't find a cached version of Flock's original post about Viking robots and life on Mars, but Google does offer an image of a much longer article.

We'll update with details as soon as we confirm more.