I don't have confirmation, but it appears that Peter Krug has died.

Here's his biography from allmusic.com:

Peter Krug would be totally forgotten today had he not, by circumstance, ended up on the very collectable first release by a major California psychedelic group. In late 1965, Country Joe & the Fish -- still a folk jugband for the most part -- put out their first two tracks, early versions of "I Feel Like I'm Fixin' to Die Rag" and "Superbird," on a four-song EP accompanying the magazine Rag Baby. Country Joe & the Fish were only on the A-side, however; the B-side was devoted to two solo acoustic performances by Krug, a San Francisco Bay Area folk singer/songwriter. The two songs were mediocre mid-'60s topical folk tunes, not helped by the drab melodies and Krug's unsteady, inexpressive vocals. "Fire in the City" mixes a Dylanesque delivery with a vague lyrical sense of apocalypse, and "Johnny's Gone to the War" was an anti-war statement. Although the original EP release on which these tracks appeared is quite rare, the Krug songs (as well as the Country Joe & the Fish ones) were reissued on Country Joe & the Fish's Collectors Items: The First Three EP's collection.

That may be all that allmusic can say about him, but we in Northern California were rather fond of him. His 1964 "Migrant Song" was published in Sing Out! Magazine and in Rise Up Singing, and Faith Petric recorded his "Geritol Gypsy." I think his most-requested song was "Woman With a Chainsaw." Here's a video of Peter singing the song. The recording quality is poor, but it may give you an idea how fun it was to listen to Peter sing his "hit":

https://www.youtube.com/watch?v=5Brv0HmOD-A

His use of the term "thunderfuck" in the song served to increase sales considerably.

Here's a better-quality recording by Remy Rodden:

https://www.youtube.com/watch?v=05xccLOY3_k

Peter, rest in peace. It was nice to know you.

-Joe-