(1) while making unauthorized use of Department property, causes loss or damage to the property; or

(2) while making authorized use of Department property, is grossly negligent in using or caring for the property and causes loss or damage to the property.

(b) If it is shown to the satisfaction of the Chief of Police that the property was lost or damaged in any manner described in Subsection (a) of this Section, there shall be incrementally deducted from the pay of the responsible member the amount of money necessary to repair or replace the article, or articles, damaged, lost or destroyed based upon the value at the time of loss or damage.