On Nov. 28, 1969, Betsy Aardsma, a 22-year-old Penn State graduate student, was stabbed to death in the stacks of Pattee Library. The case remains officially unsolved, but my guest David DeKok thinks that he knows who murdered Betsy. He believes it was a troubled and hot-tempered fellow grad student named Richard Haefner, and lays out the evidence to make his argument. His book is called "Murder in the Stacks: Penn State, Betsy Aardsma, and the Killer Who Got Away". More information on the author and the book can be found at his website: https://daviddekok.com/More from the publisher: http://www.globepequot.com/books/9781493013890This episode is sponsored by Green Chef. Go to https://www.greenchef.com/mono135 for $135 off across five boxes, and your first box ships free!