A five-year-old boy, Elias Reliford, was killed while sleeping at his home in Centennial on March 10, according to family members and police reports.

Authorities say his 11-year-old brother has been arrested and charged with first-degree murder. The case is being treated as a “very complex investigation,” and officials have not released details about how the child died.

Family members said Elias had returned home from kindergarten that day and was taking a nap while his brother was doing chores. Relatives described the two siblings as close and inseparable, saying they “always saw one together with the other.”

Elias’s great-aunt, Dawn Myles, speaking on behalf of the family, said the incident was “the most horrendous act” and that the family is struggling to cope with the tragedy. She added that they have temporarily left their home due to the emotional impact.

The accused 11-year-old is being held at a juvenile facility while the investigation continues. Under Colorado juvenile justice law, children as young as 10 can be charged with crimes, but those under 12 cannot be tried as adults.

Local school officials confirmed Elias was a kindergarten student and expressed condolences, while law enforcement officials said the case has deeply affected the community and remains under active investigation.