He has also served on assignments in  Thailand, Malaysia, Hong Kong, Taiwan, Mexico, Ecuador, Peru, Colombia, Argentina, Chile and Brazil.

Mr. Swartz attended the U.S. Department of Defense Polygraph Institute at Fort Mc Clellan, Alabama where he received training in Advanced Forensic Psychophysiology and Polygraph Examinations of Sex Offenders.

From 1986 to 1991, Mr. Swartz provided continuous polygraph service to the Bexar County District Attorney's Office in San Antonio on a wide range of criminal cases including Capital Murders, kidnappings, arsons, extortions, robberies, sexual assaults, and thefts.

In 1992, he was transferred to the United States Embassy in La Paz, Bolivia where he was the United States Goverment's only examiner stationed in South America. He was certified as a Federal examiner for the United States Department of Justice. 

Upon his return to the United States, Mr. Swartz opened a private practice for Texas attorneys, probation and parole officers, the District Courts, and companies worldwide. Adding to his criminal practice, he is now  the sex-offender examiner for the probation offices of ten separate Texas counties. He has repeatedly been requested as an authoritative expert witness in the District Courts of Harris County and elsewhere in Texas.

In addition to his private practice  Mr. Swartz actively provides comprehensive training seminars to District Court Judges, prosecutors, probation/parole departments and bar associations on current legal decisions and correct polygraph procedure, as well as providing quality control for other examiners.

John Swartz is a frequent media consultant. In 2007, he was invited to be the examiner for NBC News/Dateline on the Diane Zamora Texas Cadet Murder Case. In the same year, he assisted Univision, the Spanish network in the examination of a Texas man charged with sexual assault. In 2006, he served as a consultant to CBS/Paramount Productions on a Texas investigation involving the Dr. Phil show.

Mr. Swartz  is also  a frequent guest speaker to professional organizations as well. He has been the invited speaker to the Baylor College of Medicine's Department of Psychiatry, Bexar County District Attorney's Office in San Antonio, Texas; to the Harris County Civil Court Judges at their annual conference at the Westin La Cantera Resort in San Antonio; to the Harris County Criminal District Court Judges in Houston; to one hundred seventy five prosecutors at the Harris County District Attorneys Office; and to three hundred Appellate, District and County Court at Law Judges at the Texas Center for the Judiciary's Annual Judges' Conference in Austin; and the guest speaker for the American Probation and Parole Association's Annual Seminar in Phoenix, Arizona.