Headquarters Professional Staff
No matter what the content or extent of a testing system, the most
important components of a psychological examination are the skills and
experience of the psychologist performing the assessment. 
IFP's Principal Psychologists
Irving B. Guller, Ph.D., ABPP, FACFE
Matthew E. Guller, J.D., Ph.D.
Guillermo Gallegos, Ph.D.
Jack Leeb, Psy.D.
Gregory I. Mack, Ph.D.
Cheryl Thompson, Ph.D.
Leslie Williams, Ph.D.
Amie Wolf-Mehlman, Ph.D.
- Irving B. Guller, Ph.D., ABPP, FACFE, (Founder and Director) is a licensed psychologist in the States of New Jersey, #567; New York # 3391; and Florida, #4905. He is a Diplomate in Clinical Psychology of the American Board of Professional Psychology, a Fellow of the American College of Forensic Examiners and Professor Emeritus with the John Jay College of Criminal Justice (of the City University of New York). He is internationally known and has published extensively, appeared on network
television programs and lectured before both police and academic groups.
Dr. Guller is an associate member of the New Jersey State Association of Chiefs of Police and the International Association of Chiefs of Police (IACP), and a member of its Psychological Services Section. From 1962 to the present, he has been consultant to numerous police and other criminal justice agencies. Additional biographical information about him may be found in current editions of "Who's Who in America" and "Who's Who in the World" (both Marquis Publishing Company). - Matthew Guller, J.D., Ph.D. (Associate Director and Corporate Counsel) is a licensed attorney, admitted to the bars in New Jersey and Pennsylvania and a licensed psychologist in New Jersey (#4439) and in New York (# 16657). In addition to providing psychological services, he oversees legal matters for IFP. Dr. Guller is an associate member of IACP and a member of its Legal Services Section. He is also Associate Member of the Bergen County, Passaic County and New Jersey State Chiefs of Police Associations. He is an associate member of the American Correctional Association and a contributor to its professional journal.
- Guillermo Gallegos, Ph.D. has been a licensed psychologist for over twenty years and is licensed in both New York, and in New Jersey (# 2556). He has wide ranging experience in the assessment of dangerousness, fitness for duty and suitability for public safety employment. He has extensive experience in dealing with criminal offenders and has provided bi-lingual supervision of professional staff in numerous settings. Has also been a supervisor of residential living for the Job Corps. In recent years, Dr. Gallegos has been a principal psychological examiner for contracts involving the DEA, NJDOC and NJSP, as well as the Transportation Safety Agency (Tsa).
- Jack Leeb, Psy.D. is a licensed psychologist in the states of Maryland, Illinois, New York and New Jersey (# 3739). He is Board Certified in Forensic Examination and Psychological Assessment, and has worked with numerous Federal, state and local police agencies. He is a member of the International Society of Police Surgeons, American Federation of Railroad Police and an Associate Member of the Maryland Chiefs of Police Association.
- Gregory Irving Mack, Ph.D. is a licensed psychologist in the State of New York and recently retired as police detective and in-house psychologist with the N.Y.P.D. He has extensive experience in the assessment and treatment of police officers and police candidates. He was appointed a professor with the John Jay College of Criminal Justice of the City University of New York. Dr. Mack joined IFP in 2007 and provides examination services in our New York City office.
- Cheryl Thompson, Ph.D. is a clinical psychologist licensed in New York and New Jersey. She is Professor of Psychology and a member of the Doctoral Faculty of Seton Hall University. She has been involved in police assessment since 1989. She is the former Chair of the Minority Affairs Committee of the New Jersey Psychological Association. She also conducts evaluations of juvenile offenders, and others, and is certified as an expert in State and Federal courts.
- Leslie J. Williams, Ph.D. Has been a licensed psychologist for over twenty years and a police specialist for much of that time. He has been Psychological Consultant to the Social Security Administration and an Employee Assistance Panelist with the New Jersey State Police for over ten years. He has been an adjunct professor with both the County College of Morris and the Sussex County College, and has been certified as an expert witness in both State and Federal courts.
- Amie Wolf (Mehlman), Ph.D. is a licensed psychologist in both New York and New Jersey(# 3227). She has been an examiner with IFP since 1994 evaluating law enforcement and other public safety candidates. as well as conducting a variety of other forensic assessments. She frequently appears as an expert witness in State courts.