THORNTON, Colo. (CBS4)– An 18-year-old man who was arrested in Thornton, accused in the death of an infant, has been formally charged with first-degree murder.

Police arrested Isaiah Marquez after the 3-month-old was found not breathing at a home on Gale Boulevard near Thornton Parkway on May 1.

Isaiah Marquez (credit: Thornton Police)

The infant was rushed to the hospital where the child was pronounced deceased.

Medical staff stated the injuries to the child were described as non-accidental trauma. The cause of death will be determined by the Adams County Coroner’s Office.

Marquez is described as the boyfriend of the child’s mother.

Marquez was advised of the charge on May 5. He is scheduled to appear in court on July 7 in Adams County Court.