Norman A. Gahn

Norman A. Gahn is a national expert in the field of DNA prosecution. He has been an Assistant District Attorney with the Milwaukee County District Attorney’s Office since July 1984. He pioneered the concept of issuing sexual assault warrants by DNA profile, and not by name, at the time of charging an unknown perpetrator with an offense. 

In 1999, he issued Milwaukee County’s first John Doe DNA warrant for the arrest of a serial rapist who was only identified by his genetic code. This work has enhanced and changed the prosecution of sexual assault cases. It allows the court to retain jurisdiction of a sexual assault case. If the name of the perpetrator is discovered after what would have been the expiration of the statute of limitations, the case is still open. 

DNA technology is often used for identification in sexual assault cases–providing proof beyond a reasonable doubt. It corroborates victim statements and gives evidence, support and credibility to their testimony. It is used to establish the presence of someone at a crime scene and impeach the statement of criminal defendants. DNA can also be used to show the absence of someone at a crime scene and exonerate the innocent. 

Mr. Gahn’s expertise in forensic science has resulted in many successful prosecutions of sexual predators, and consequently saved others from becoming victims. His work has played a key role in ensuring that technology and science have a presence in criminal investigations and prosecutions. He also uses DNA technology to build a compelling case against the incarcerated. When a DNA match is found and the statute of limitations has expired, the evidence is compiled and given to the parole board for future use in commitment hearings. He has lectured extensively around the country on the use of DNA evidence in the courtroom. 

The Federal Bureau of Investigation has formally recognized him as a pioneer in DNA technology in the courtroom and the National Institute of Justice has formally recognized him as an innovator in the field of DNA evidence.