IMMUNITY FOR WITNESSES IS DECIDED SOLELY BY PROSECUTORS, WHO MAY DECLARE THEIR INTENTIONS BY OBTAINING A FORMAL COURT ORDER, BY WRITING A LETTER, OR BY MAKING AN ORAL COMMITMENT. ASIDE FROM THE PHILOSOPHICAL IMPLICATIONS ARISING FROM THE IMMUNITY POWER OF PROSECUTORS, THE MORE IMMEDIATE AND PRACTICAL PROBLEM FOR CRIMINAL DEFENSE LAWYERS IS HOW TO DEAL WITH THE IMMUNIZED GOVERNMENT WITNESS DURING THE TRIAL. THE DEFENSE LAWYER MUST MAKE THE JURY UNDERSTAND THE NATURE OF IMMUNITY AND THE POTENTIAL UNRELIABILITY OF THE IMMUNE WITNESS. MANY PROSECUTION WITNESSES HAVE MADE STATEMENTS TO AGENTS OR GRAND JURIES THAT ARE DIFFERENT FROM THEIR TRIAL TESTIMONY. MOTIVATIONS AND EXPECTATIONS OF WITNESSES ARE LEGITIMATE AREAS OF INQUIRY, AND THE DEFENSE LAWYER MUST ESTABLISH THE BUYER-SELLER RELATIONSHIP BETWEEN WITNESSES AND PROSECUTORS. THE FOLLOWING STANDARDS REGARDING IMMUNITY ARE RECOMMENDED: THE GRANT OF IMMUNITY SHOULD BE IN THE PUBLIC INTEREST, WITHOUT COUNTERVAILING LEGAL INTEREST; THE GRANT OF IMMUNITY SHOULD BE SOUGHT SOLELY FOR WITNESS INFORMATION; AND THE NEED FOR TESTIMONY SHOULD BE ESTABLISHED, ALONG WITH THE FACT THAT IMMUNITY IS THE ONLY MEANS OF OBTAINING SUCH TESTIMONY. DIFFERENT CONCERNS POSED BY VOLUNTARY AND INVOLUNTARY WITNESSES WHO HAVE BEEN GRANTED IMMUNITY ARE DISCUSSED. CASE LAW IS CITED. (DEP)