"I do not expect, nor will I accept forgiveness for what he has done. I realize there is nothing positive to be taken from this incident," Erik von Brunn wrote in letter to ABC News.
"My father's beliefs have been a constant source of verbal and mental abuse my family has had to suffer with for many years," the 32-year-old wrote. "His views consumed him, and in doing so, not only destroyed his life, but destroyed our family and ruined our lives as well."
As his father sits in a hospital in critical, but stable condition, the younger von Brunn tried to express his regrets to the family of Stephen Tyrone Johns, the museum guard who opened the door for the 89-year-old neo-Nazi only to have his courtesy repaid with a bullet.
Holocaust Museum Shooting Witness
"I cannot express enough how deeply sorry I am it was Mr. Johns, and not my father who lost their life [Wednesday]," Erik von Brunn said. "It was unjustified and unfair that he died, and while my condolences could never begin to offer appeasement, they, along with my remorse is all I have to give."
Erik von Brunn also used his letter to address those who might express admiration for the violent stand taken by his father.
"For the extremists who believe my father is a hero: it is imperative you understand what he did was an act of cowardice. To physically force your beliefs onto others with violence is not brave, but bullying. Doing so only serves to prove how weak those beliefs are. It is simply desperation, reminiscent of a temper tantrum when a child cannot get his way. Violence is a cop out; an easy answer for an ignorant problem."