Section 13-637. Pension to members of police force disabled in military or naval service of the United States

The board of trustees of the  police  pension  fund  shall  have power to retire from membership in the police
  force and thereupon to grant an annual pension to  any  member  of  such
  department,  who,  while in the military, naval or marine service of the
  United States has become permanently disabled physically or mentally, so
  as to be unfit to perform the full duty of his or her employment in such
  department. Such  pension  shall  not  exceed  one-half  of  the  annual
  compensation  earned by such member at the time of his or her retirement
  and shall be paid in like manner as pensions are paid out of the  police
  pension fund of such city.