A bail hearing has revealed gruesome details of the death of 5-year-old Jeremiah Oliver, of Fitchburg, nearly a decade ago.

Alberto Sierra Jr., 32, was arraigned last week in Worcester Superior Court on charges of murder and disinterring a body for the death of Oliver, whose body was found in a suitcase on the side of Interstate 90 in Sterling on April 18, 2014. Sierra was at the time the boyfriend of Oliver’s mother, Elsa Oliver.

The state Office of the Chief Medical Examiner determined Jeremiah’s death a homicide, but the cause of death was undetermined: “homicidal violence of undetermined etiology.”

On Friday morning, Sierra was ordered held without bail.

News sources report that during that bail hearing, prosecutors outlined some gruesome new details about the case, including the allegation that Oliver may have been killed because he was sticking up for his mother while she was in a physical altercation with Sierra.

According to WCVB, prosecutors say that young Oliver was kept in a kitchen closet for “discipline,” but emerged when his mother left the room due to receiving a head injury and the boy allegedly said to Sierra, “Don’t hurt my mommy.”

Prosecutors then say that Sierra slammed Jeremiah’s head into the ground, an injury that would result in the boy’s death the next day.