SEATTLE, Wash. -

When 13-year-old Eddie Holmes was fatally shot in the chest by one of his friends, he was one of more than a dozen Washington state children who were injured or killed since 2014 in accidental shootings.

The federal government no longer tracks these cases, but an investigation by The Associated Press found that in 2015, almost 6 percent of Washington households kept loaded guns unsecured. In 2014 alone there was one death and six injures resulting from accidental shootings of children younger than 18.

That data was collected by the state Department of Health.

The investigation found that some of the gun owners in these cases faced charges, while others did not. Prosecutors say it's difficult to prove the gun owners were criminally negligent when they left their firearms within reach of children.

Since Holmes's death, his mother has pushed for a new law requiring the safe storage of firearms.