Katherine Maris Mattes

Katherine Mattes specializes in criminal litigation at all levels of practice, including trial, appellate, post-conviction, federal habeas, and clemency.  She has expertise in the intersection of criminal law and mental illness, specifically mental competency to proceed and the insanity defense. She has been at the forefront of criminal justice reform in the state of Louisiana, and her advocacy has transformed the lives of hundreds of incarcerated people, especially those living with mental illness, juveniles sentenced to life-without-the-possibility-of-parole, and people serving life sentences under Louisiana’s “habitual offender” law.

She has written Louisiana practice manuals on competency to stand trial, the insanity defense and representing criminalized survivors of intimate violence.  She has served on two legislative task forces; one focused on competency to stand trial laws, and the other on creating a more trauma-informed criminal legal system focused on criminalized survivors of intimate partner violence. She has testified before the Louisiana and Texas legislature on issues relating to competency to stand trial, juvenile’s sentenced to life-without-parole after Miller v. Alabama, and Louisiana’s habitual offender statutes. She teaches in the Forensic Division of the Tulane Medical School Department of Psychiatry and is a co-founder of the Orleans Parish Forensic Mental Health Coalition which later became the New Orleans Behavioral Health Council run by the New Orleans City Health Department.

In 2019, along with Co-Director, Becki Kondkar, Mattes founded the Women’s Prison Project, which seeks freedom for women unjustly incarcerated for killing an abusive partner or for participating in crimes under the duress of an abusive partner.  The Project has secured freedom for 7 women serving life sentences in its first two years of operation and has been recognized for “Excellence in a Public Interest Project” by the Clinical Legal Education Association.

Mattes has also been recognized for her work in the aftermath of Hurricane Katrina to rebuild the Orleans Parish criminal legal system.  Mattes accepted the Clinical Legal Education Association Award for Excellence in a Public Interest Project for work identifying, locating, and representing people who had been incarcerated in Orleans Parish Prison and been displaced by the post-storm evacuation.

Prior to joining the Tulane Law School faculty in 2002, Mattes was a deputy public defender in San Diego, CA; a staff attorney at the Innocence Project New Orleans; and Assistant Special Counsel for the Judiciary Commission of Louisiana.