Section 610.50. Securing attendance of witness by subpoena; fees

1.    A  witness  subpoenaed  by  the  people  in a criminal action is
  entitled to the same fees and mileage as a witness in  a  civil  action,
  payable by the treasurer of the county upon the certificate of the court
  or  the  clerk  thereof, stating the number of days the witness actually
  attended and the number of miles traveled by him in order to attend.  In
  any such action, the court may, by order, direct the county treasurer to
  pay to such witness  a  further  reasonable  sum  for  expenses,  to  be
  specified in the order, and the county treasurer, upon the production of
  the  order  or  a  certified  copy thereof, must pay the witness the sum
  specified therein out of the county treasury.   Such certificates  shall
  only be issued by the court or the clerk thereof, upon the production of
  the affidavit of the witness, stating that he attended as such either on
  subpoena  or  request  of  the  district  attorney,  the number of miles
  necessarily traveled and the duration of attendance.  An officer in  any
  state  department  who  attends  as  a witness under this section in his
  official capacity, or in consequence of any  official  action  taken  by
  him,  and  who  receives  a  fixed  sum  in  lieu of expenses, or who is
  entitled to receive the actual expenses incurred by him in the discharge
  of his official duties, is  not  entitled  to  the  compensation  herein
  provided.
    2.   A witness subpoenaed by the defendant in a criminal action is not
  entitled as of right to witness and mileage fees, but the court  may  in
  its  discretion,  by order, direct the county treasurer to pay to such a
  witness a reasonable sum for expenses, to be  specified  in  the  order.
  Upon the production of the order or a certified copy thereof, the county
  treasurer  must  pay  the  witness the sum specified therein, out of the
  county treasury.