Section 17-347. Excused behavior

No dog shall be declared dangerous pursuant
  to  § 17-345  if  the  threat,  injury, or damage caused by such dog was
  sustained by a person  who,  at  the  time,  was  committing  a  willful
  trespass  or  other  tort upon the premises occupied by the owner of the
  dog, or was tormenting, abusing, or assaulting the dog, or has,  in  the
  past,  been  observed or reported to have tormented, abused or assaulted
  the dog, or was committing or attempting to commit a  crime.  Nor  shall
  any dog be declared dangerous if it was responding to pain or injury, or
  was protecting itself, its kennels, or its offspring. If the trespass is
  determined  to be of an innocent nature, the commissioner may, depending
  on the circumstances, and in accordance with the procedures set forth in
  section 17-345, find the dog to be dangerous.