Modes  of  discovery such as the taking of deposition,  may be allowed in criminal cases, but it is subject to the sound discretion of the court

WHY ARE MODES OF DISCOVERY ALLOWED?

     The purpose is not to frustrate the ends of justice  
     Purpose also is to obviate proceedings
     A party may have a witness for his behalf but due to reasonable circumstances,   the   witness  essential   to   his   case   would   be unavailable and will not be able to attend