CARTER COUNTY, Tenn. -

We're learning new facts in the investigation of a four-year-old's death in Carter County. A 13-year-old is now facing homicide charges after authorities say the toddler was shot in the head with a BB gun on July 2.

Carter County Sheriff Chris Mathes tells News 5 the charges aren't to ruin the teen’s life, but to make sure it doesn't happen again.

Four-year-old Coty Cox was left inside his home off of Lover's Lane in Carter County in the care of his 13-year-old cousin and 10-year-old brother.

We've learned now the District Attorney's office has made the decision to file reckless homicide charges against the teen who was supposed to be watching the child and his brother. "A summons has been issued for the juvenile he'll have a court date here. You handle a juvenile different than you do adults. At this point we don't think he's a threat to society or anything else," adds Mathes.

Mathes tells us the two boys told authorities Coty fell off the bed and hit his head, but Mathes says evidence showed otherwise. "Through the investigation we disproved the thoughts that the child actually fell, and it can't be more obvious than the removal of a BB shot to the head," says Mathes.

After digging through the misinformation, Mathes says the D.A.'s office decided to charge the teen with reckless homicide. "It’s not intentional, it’s what it says -- it's a reckless act that someone has a conscious disregard of the risk to another person," adds Assistant District Attorney Dennis Brooks.

The child's mother told officers she had gone to the store and says she was only gone for a short time. Mathes tells us as of now the mother isn't facing any charges. "We have our concerns. We looked at those things and a lot of people might criticize us, but you have to look at all factors of any juvenile and what you're comfortable with as a parent," says Mathes.

Mathes says they don't want to ruin the teen's life, but they want to help him. "Getting in the system and trying to not destroy a 13-year-old's life, but get them to where obviously it doesn't happen again. They have to live through this too," adds Mathes.

Mathes tells us they recovered multiple BB guns from the home. One of them was a pump model that can be pumped multiple times to get more velocity.

The 13-year-old will appear in the Carter County court. His name will not be released.

Brooks tells us he's skeptical this case would go to adult court because of the age of the defendant and it being a reckless act.