When a large dog attacked and killed a small one on a leash being walked by a child three weeks ago in Lewiston, we called it “horrific.”

Sadly, it’s happened again and we can’t think of a better adjective.

Sunday in Livermore Falls, a 20-pound terrier on a leash being walked by three teens was attacked and killed by a mastiff-Rottweiler mix, two breeds of which males often weigh between 90 and 120 pounds.

The smaller dog was trained as a therapy dog. The larger dog was loose when it set upon the smaller dog and killed it.

“We’re absolutely devastated,” Bethany Miller, the owner of the 4-year-old terrier told the Sun Journal. The attack on their beloved pet was so traumatic that she plans to get counseling for her children.

When she does, she should send the bill to Martin Vining, the owner of the roaming dog.

He was served with a summons Tuesday for having a dangerous dog, having an unlicensed dog and having a dog at large. The same dog bit a mail carrier three years ago.

“I cannot control what two dogs do when they get into it,” Vining told the Sun Journal, revealing the real problem — there are more problem dog owners than problem dogs.

The Livermore Falls incident is a near carbon copy of the one that occurred in Lewiston last month when a pair of huskies being walked by a Lewiston woman mauled and killed a dachshund being walked by a 9-year-old girl.

The woman walking the huskies was simply unable to control them.

That incident followed another in April, also in Livermore Falls, in which an 11-year-old boy was severely mauled by a pit bull inside a home he was visiting.

There are rewards to dog ownership and there are responsibilities, one of which is simple: If you own an animal, you own everything it does. All day. All night. On weekends and holidays. When it’s on a leash or running loose.

That responsibility ranges from picking up its poop to keeping it from mauling other dogs and children.

Sadly, too many dog owners only learn this in a courtroom.