The state medical examiner’s office was unable to determine how 2-year-old Tristan Matthew Blue died in December 2014 because of the poor condition of his remains, according to autopsy results released this week.

The toddler’s parents had reported him missing on Christmas Eve, but they were arrested the next day. Authorities found Tristan’s remains on Dec. 26 in Beaver Dam Lake, a branch of Falls Lake.

Steven Blue, 33, is being held without bail on a first-degree murder charge.

Tristan’s mother, Briana Loriel Dangerfield, 26, is being held in lieu of $1 million bail on charges of accessory after the fact of murder; altering, stealing or destroying criminal evidence, destroying remains to conceal an unattended death and misdemeanor child abuse.

According to the autopsy results written by Dr. Susan E. Venuti, “Due to limited tissue available for examination, a specific anatomic cause of death cannot be determined.” She added, however, “The condition and disposal of the remains indicate a homicidal intent.”

The boy was identified through DNA comparison with his parents, the report said.

Police brought to the medical examiner what were described as “fragments” of clothing, body parts and an advertising circular. All showed evidence of burning, the report said.

The boy’s right forearm showed diagonal cuts, Venuti wrote. She found “evidence of fragmentation with blunt and sharp-force trauma, thermal burns and concealment.”

A Raleigh police search warrant said that Tristan died at the Portree Place apartment where the family lived.