A sheriff's detective has told a judge he collected firearms, large amounts of ammunition and bullet casings from the New Mexico home where authorities say three children and their parents were killed by the young siblings' older brother in 2013.

Bernalillo County Sheriff's Deputy Miguel Rivas took numerous photos and collected evidence at the Griegos' home south of Albuquerque the night authorities discovered the bodies of five family members inside.

Nehemiah Griego was 15 when authorities say he opened fire inside the home.

A hearing is underway in Albuquerque this week to determine whether he should be sentenced as a juvenile or an adult.

Now 18, Griego pleaded guilty in October to charges of second-degree murder and child abuse resulting in death.