THE CASE SAMPLE WAS OBTAINED FROM FBI AND NATIONAL CRIME INFORMATION CENTER (NCIC) RECORDS FOR SEPTEMBER AND OCTOBER 1977. THE FINAL SAMPLE OF 359 SUBJECTS WAS GLEANED FROM FBI FILES ON 194 SUBJECTS (INVOLVED IN 129 INTERSTATE AUTO THEFTS) WHO HAD BEEN REFERRED TO STATE OR LOCAL AUTHORITIES FOR PROSECUTION, AND FROM 1,922 NCIC REPORTS OF INTERSTATE AUTO THEFTS (FULL INFORMATION OBTAINED ON 306 SUBJECTS INVOLVED IN 267 CASES). ALL AGENCIES TO WHICH SUBJECTS WERE REFERRED FOR PROSECUTION WERE CONTACTED BY MAIL OR TELEPHONE FOR INFORMATION ABOUT COSTS OF TRANSPORTING SUBJECTS, PROBLEMS WITH PROSECUTION, AND CASE OUTCOMES. THE SURVEY FINDINGS SHOW THAT THE MAJORITY OF INTERSTATE AUTO THEFT SUSPECTS ARE EITHER PROSECUTED NOR REFERRED TO THE THEFT JURISDICTION FOR PROSECUTION. NEARLY HALF OF ALL INTERSTATE AUTO THEFT SUBJECTS PRESENTED TO U.S. ATTORNEYS ARE NEITHER PROSECUTED FEDERALLY NOR REFERRED. PROSECUTION RATES ARE LOWEST IN LARGE JURISDICTIONS WITH HIGH CRIME AND AUTO THEFT RATES. UNLIKE AUTO THEFT IN GENERAL, INTERSTATE AUTO THEFT IS PREDOMINANTLY AN ADULT CRIME. THE STATUTE PROVIDING FOR TRANSPORT OF INTERSTATE THEFT SUSPECTS AT FEDERAL EXPENSE RARELY IS USED FOR TRANSPORTING ADULT INTERSTATE AUTO THEFT SUSPECTS. THE COST OF TRANSPORTING A SUBJECT BACK TO THE THEFT JURISDICTION IS A RELATIVELY UNIMPORTANT FACTOR IN THE STATE ATTORNEY'S DECISION TO PROSECUTE. THAT DECISION IS BASED PRIMARILY ON THE STRENGTH OF EVIDENCE AGAINST THE SUSPECT, THE LIKELIHOOD OF INCARCERATION AFTER CONVICTION, THE WILLINGNESS OF THE VICTIM TO PROSECUTE, AND THE PRIORITY OF OTHER OFFENSES FOR PROSECUTION. RECOMMENDATIONS FOR ACTIONS BY THE U.S. DEPARTMENT OF JUSTICE TO INCREASE PROSECUTION OF INTERSTATE AUTO THEFT CASES ARE PRESENTED. SUPPORTING DATA AND DOCUMENTATION ARE PROVIDED. (LKM)