Harmon is best known for her roles in "Law & Order" and "Rizolli & Isles."
She shared a post on social media Monday saying her family is "completely traumatized & beyond devastated at the loss of our beloved boy & family member."
In her post, Harmon wrote: "He got out of his car, delivered the food, & THEN shot our dog...The police let him go b/c he claimed 'self-defense'. He did not have a scratch or bite on him nor were his pants torn."
According to the Charlotte-Mecklenburg police, the driver said the dog attacked him while he was delivering food to the family's home on Saturday.
He was defending himself, the driver said, when he fired the single gunshot.
No charges have been filed.