DA SealDA McMahon




Executive ADA Timothy J. Koller
Timothy J. Koller
Executive Asistant District Attorney

Timothy J. Koller earned a bachelor’s degree in political science and business from St. John’s University in 1977, and went on to earn his J.D. in 1980 from Pace University School of Law. He was appointed an Assistant District Attorney at the Richmond County District Attorney’s Office on Aug. 11, 1980 and began his career as a prosecutor in the office’s Criminal Court Bureau. In 1982, Koller was transferred to the Supreme Court Bureau as a staff assistant assigned to prosecute felonies. From 1986 through 1989, Koller served as the Chief of the Career Criminal Unit, where he was responsible for the prosecution of repeat felony offenders. In 1989, Koller was appointed Chief of the Investigations Bureau, a position he held until 1991 when he was tapped to serve as the Chief of the Supreme Court Bureau, a post Koller held for 14 years.

In August of 2005, Koller was named Executive Assistant District Attorney, where he was responsible for the day-to-day legal operations of the Richmond County District Attorney’s Office. In 2016, Koller continues to serve under District Attorney Michael E. McMahon as his Executive Assistant District Attorney, the fifth District Attorney under whom Koller has served during his more than 35 years as a prosecutor making him the longest-serving prosecutor on Staten Island.

A career prosecutor, Koller has lectured and presented at numerous continuing legal education programs at the NYPD Police Academy; the New York State Division of Criminal Justice Services Basic Prosecutors’ Course; the New York Prosecutors Training Institute’s Summer College; DAASNY Summer and Winter Conferences; the New York State Attorney General’s Office; other District Attorneys’ Offices; the Oregon Bar Association Criminal Justice Section; Safe Horizon’s Survivors of Homicide training. Since 2003, Koller has taught Criminal Law at the undergraduate level, and Constitutional Law on the graduate level, at St. John’s University as an Adjunct Assistant Professor.

Over a decade ago, Koller created corporeal lineup protocols for his office, and has presented at various identification evidence training programs. As an original member of the DAASNY Best Practices Committee, Koller was part of a group that formulated Identification Protocols for New York State’s law enforcement community. In 2014, he was invited to serve as a pre-publication reviewer for a National Academy of Sciences Publication, “Identifying the Culprit: Assessing Eyewitness Identification”. During his career, Koller has received a number of awards and recognitions, including the Thomas E. Dewey Medal in 2005 and the Robert M. Morgenthau Award in 2012.