Episode 093: Joseph DiZinno – FBI Laboratory, Katrinak Murder Case

Retired agent Dr. Joseph Dizinno, DDS. served in the FBI for 22 years.

Prior to joining the FBI, Dr. DiZinno, who received a Doctor of Dental Surgery Degree from The Ohio State University in Columbus, Ohio, owned and operated a family dental practice. He was initially assigned to the Washington Field Office where he investigated reactive crimes. After three years in the field, he was promoted and transferred to the FBI Laboratory where he began to specialize in the examination of hairs and fibers. Dr. DiZinno served as a critical investigative resource on many high-profile cases including dental and DNA identification at the Branch Davidian Cult fire, kidnappings, and major extortion cases.

In a this episode, Dr. DiZinno reviews the functions of  FBI Laboratory and the investigation of the tragic murders of Joann Katrinak and her baby Alex where mitochondrial DNA analysis was first applied to forensic casework.

He was part of the research team that developed and validated forensic mitochondrial DNA analysis capability which enabled the FBI to obtain a DNA profile from evidence containing small or degraded quantities of DNA from hair, bone, teeth, and bodily fluids. Dr. DiZinno ended his Bureau career as the Director of the FBI Laboratory where he led more than 550 FBI Laboratory personnel, providing forensic examinations, technical support, expert witness testimony, and training to federal, state, and local law enforcement agencies and responding to events all around the world. Currently, Dr, DiZinno is a faculty member at George Mason University in Fairfax, Virginia where he teaches forensic science to undergraduate and graduate level students in the Forensic Science Program.

Laboratory Director (Retired)

Joseph DiZinno

4/20/1986 – 2/1/2008










The following are links to FBI Website and YouTube features about the FBI Laboratory and news paper articles about the investigation and trial of the tragic murders of Joann Katrinak and baby Alex:

FBI Website – The FBI Laboratory

NatGeoTV (Video) – 8/17/2015:  Modern Marvels -Inside the FBI Crime Laboratory


The Morning Call – (Photo Gallery):  Patricia Rorrer and the murders of Joann and Alex Katrinak

People Crime (Video) – 3/2/2017:  ID Examines Controversial 1994 Case of Woman Convicted of Murdering Ex-Boyfriend’s Wife and Son

Dr. Joseph DiZinno was assigned to the FBI Laboratory for 19 of his 22 years in the FBI and was its Director at the time of his retirement. The FBI Lab is a state-of-the-art facility located in Quantico, Virginia.









The mission of the Scientific Response and Analysis Unit (SRAU) is to provide scientific, technical, and forensic support to FBI criminal and intelligence investigation.











Jerri Williams

View posts by Jerri Williams
Jerri Williams, a retired FBI agent, author and podcaster, jokes that she writes about the FBI to relive her glory days. After 26 years with the Bureau specializing in major economic fraud and corruption investigations, she calls on her professional encounters with scams and schemers to write police procedurals inspired by true crime FBI cases in her Philadelphia FBI Corruption Squad crime fiction series featuring flawed female FBI agent Kari Wheeler. Jerri’s FBI for Armchair Detectives nonfiction series enables readers to discover who the FBI is and what the FBI does by debunking misconceptions about the FBI in books, TV, and movies. Her books are available as ebooks, paperbacks, and audiobooks wherever books are sold. She’s also the host of FBI Retired Case File Review, a true crime podcast with more than 300 episodes available on all popular podcast apps and YouTube.

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