Note: This was found in a Berkeley coffeeshop, written on a sheet of foolscap.

Berkeley, CA — Dr. Lior Pachter is a professor at UC Berkeley, and a highly respected researcher in bioinformatics and genomics. By all accounts, he is a mild-mannered colleague and somewhat disorganized but entertaining and friendly as a teacher. What few of his colleagues seem to realize is that, underneath this unremarkable exterior, there may lurk a sociopathic monster named @lpachter.

“Lior? He’s a nice guy — reclusive, but then he’s really a mathematician, so that’s normal. We chat in the hallway pretty frequently.” This quote, from someone who asked not to be identified as they shared an office wall with Dr. Pachter, typifies the response from his many colleagues. Dr. Pachter is well liked by his colleagues and rarely, if ever, fights or argues with them, except in the gladiatorial arena of faculty meetings. Background interviews going back to high school in Palo Alto confirm that Dr. Pachter was, by all accounts, an intelligent child with a muted personality.

In stark contrast to this mild-mannered person, the blog ( and Twitter account (@lpachter) that are published under Dr. Pachter’s name are anything but muted. Interspersed with learned dissertations on mathematical and biological concepts, @lpachter writes scorching condemnations on a regular basis, covering James Watson’s alleged racism, King Abdulaziz University’s alleged buying of citation-heavy faculty to improve their world ranking, Terry Speed’s decision to work on the same topic for more than one paper, Titus Brown’s abuse of arbitrary thresholds, ENCODE’s misuse of scientific reasoning, and just about everything to do with Manolis Kellis. These blog posts are long, discursive, and savage, with a bloodthirsty ardour that is rare to find outside of anonymous peer review. In large part because of this unusual juxtaposition between erudition and viciousness, in just 18 months this blog has led to a cult following, with journal clubs devoted to reading @lpachter’s latest “target”.

Nonetheless, scientists diverge on the value and visibility of @lpachter’s blog posts. Alicia Oshlack, a long-time collaborator of Terry Speed’s and self-proclaimed friend of Lior’s, said, “I’ve read one or two of the blog posts; they seem fine to me, if unnecessarily contentious. I don’t really use the Internet much so I haven’t seen the reaction but I can’t imagine anyone objects all that much.” In contrast, another bioinformatician who refused to go on the record referred repeatedly to @lpachter as “an a-hole has-been.” These split reactions were typical of many different community members.

Intrigued by @lpachter’s posts and these divergent reactions, I set out to understand the man behind the spleen. What I found was far stranger than I could have imagined.

When asked directly in person, Dr. Pachter would not admit to being @lpachter, but he also did not deny it. Rather, after three separate and distinct direct questions on this topic, Dr. Pachter simply ignored the question and changed the topic. A fourth attempt to ask led to him muttering something about “needing to understand Wiles’s proof” and my subsequent ejection from his office; all further attempts to meet were turned down. Dr. Pachter also did not return e-mails or phone calls.

When @lpachter was asked on Twitter, he readily admitted to being Dr. Pachter, but would not return e-mails from an official account; instead, I received e-mail responses from, an account of unknown provenance.

All attempts to confirm that @lpachter is, in fact, Dr. Lior Pachter, have failed. However, the circumstantial evidence is great: all blog posts are made between 4pm and 2am California time, which is prime working hours for a mathematician; @lpachter tweets on the same schedule. @lpachter must be a deeply educated bioinformatician, from simple examination of the content of the blog posts. And judging from some of the insider knowledge of conference peer review of specific papers, @lpachter is an eminent scientist in the field. All signs point to Dr. Pachter and @lpachter being the same person. However, based on interviews with Dr. Pachter, my firm belief is that @lpachter and Dr. Pachter are one and the same — two personalities in the same physical body. I seek next to confirm this hypothesis.