BEXAR COUNTY – The medical examiner's office has identified the 4-year-old boy who was fatally attacked by his family's dog Sunday afternoon as Noah Trevino.

According to the Bexar County Sheriff's Office, Noah was playing in the backyard of his home in the 8900 block of Twincreek Farm. Bexar County Sheriff Javier Salazar said the dog was tied up when he attacked the child.

"It appears that the child may have gotten too close to the dog," Salazar said. "One of the relatives of the child actually looked out into the backyard and saw that the dog had his mouth around the little boy's neck and was shaking him."

Salazar said Noah was found lifeless. Family members attempted to administer first aid, but were unsuccessful. He was airlifted to the hospital where he was declared dead.

In response to the fatal dog attack, Salazar said a child should never be left alone with a dog, even if it's not known to be vicious.

"This was a family dog," Salazar said. "Even if the dog doesn't show any outward signs of aggression, sometimes they can be unpredictable. So, it's best to always be vigilant when you're dealing with a small child and a dog like that."

Bexar County Animal Control took the dog, which they described as a "mixed large breed." It will be held for overnight observation and tested for rabies before being euthanized, according to authorities.