A free public lecture about the role and duties of a medical examiner titled "Introduction to the Medical Examiner" will be given at 12:20 p.m. Oct. 15, in 112 Borland Building on the Penn State University Park campus. Roger Mitchell Jr., a board-certified pathologist at the New Jersey Medical Examiner Service, will present the lecture, which is the second of three presentations on forensic science and its use as a law-enforcement tool in Penn State's 2012 Forensic Science Lecture Series.