He currently serves as the director of the department's graduate program. Katz earned his Ph.D. in Criminal Justice from the University of Nebraska at Omaha in 1997. He is currently involved in two studies examining responses to community gang problems. He is the project director for a National Institute of Justice study of the police response to gangs in four sites: Phoenix, Albuquerque, Las Vegas, and Inglewood (California). In addition, he is working with the Office of Juvenile Justice and Delinquency Prevention and the City of Mesa (Arizona) to evaluate the effectiveness of the Mesa Gang Intervention Project. His publications include numerous articles on community policing, policing gangs, and drugs and crime.Walker, Samuel is the author of 'Police in America An Introduction', published 2007 under ISBN 9780073527925 and ISBN 0073527920.