Angie Harmon and her family really didn’t have a happy Easter . . . because their dog Ollie was shot and killed by an InstaCart deliveryman.  (!!!)

According to an Instagram post, the man delivered food to Angie’s house, then shot Ollie, claiming the dog had attacked him and it was self-defense.  And the cops let him go.

But Angie says the driver, quote, “didn’t have a scratch or bite on him, nor were his pants torn.”  Also, she says their security camera was in the house charging, so he knew he wasn’t being recorded.

She adds, quote, “He shot our dog with my daughters and myself at home and just kept saying, ‘Yeah, I shot your dog.  Yeah I did.’  We are completely traumatized and beyond devastated at the loss of our beloved boy and family member.”

InstaCart suspended the guy and is cooperating with investigation, but TMZ spoke with the cops, and it sounds like they might not be charging him.