The National Park Service is investigating an incident in which a visitor was shocked with a stun gun over the weekend by a park ranger at the Petroglyph National Monument in New Mexico. Darrell House, a Native American and Marine veteran, was with his sister Sunday afternoon walking his dog at the park, where he often prays and meditates, according to news reports. As he was walking, he moved off a trail to make way for a group of walkers and to adhere to social distance protocols, he said.