The non-confrontational way is SSS: Shoot, Shovel and Shut up.

Most areas (esp rural areas) have laws that say any hunter or homeowner or farmer can shoot on sight any predator that is chasing/harassing/killing wildlife, livestock or family pets. The killer-dog owner usually doesn't have a legal leg to stand on.

Talk to your local law enforcement and get some advice.

Ask around to see who the dogs might belong to.

Take photographs and date them.

Teach your wife how to shoot.

Sue