BROOMFIELD, Colo. -- An arrest affidavit indicates that a 25-year-old man used an ax to kill his 4-year-old nephew in a Colorado home.

Emanuel Doll was arrested April 27 on a homicide charge after the boy was found dead with what Broomfield police spokeswoman Joleen Reefe has described as a "massive amount of trauma." The affidavit was recently unsealed after a petition by media groups, reports the Denver Post.

Doll's parents, who were in the home at the time, told investigators their grandson went down to the basement where Doll was and then they heard loud noises that sounded like "a pillowcase loaded with items hitting the floor." When they asked what the sounds were, Doll responded, "nothing," and came upstairs, reports the Denver Post.

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When they went downstairs, they found the child dead with an ax near his body.

Police officers who found Doll in the backyard say he was covered in blood, the paper reports.

Court documents don't indicate if he has hired an attorney.