An order directing examination of a witness conditionally must be based upon the ground that there is reasonable cause to believe that such witness:

1. 1. Possesses information material to the criminal action or proceeding in issue; and

2. 2. Will not be amenable or responsive to legal process or available as a witness at a time when his testimony will be sought, either because he is:

   1. (a) About to leave the state and not return for a substantial period of time; or
   2. (b) Physically ill or incapacited.