What is best paying job in the criminal justice field

Probably Defense Attorney. They are specialized and often have very wealthy corporate clients in areas such as White Collar Crimes, Securities Fraud, Tax Evasion, etc. It is not uncommon for partner-level defense attorneys to bill $300/hour for their work and $500-$1000 per hour for courtroom appearances during the trial.

Remember that Defense Attorneys are private - they are hired by people who can afford them. People who cannot afford them resort to lowly-paid Public Defendants.

Prosecutors are state employees who make good but not generally great money, $80-$100K per year is typical. Everyone else (Cops, crime scene experts, lab techs) on the prosecution side generally makes less than this amount.

Another good job, if you can get it, is expert witness. These are people who testify in court about technical or scientific issues such as DNA evidence, psychology, hair & fiber evidence, etc. They work as consultants and generally are paid handsomely for courtroom appearances.