Aurora Police Department officers arrested a 24-year-old man Saturday in connection with a 4-year-old boy’s death.

Police took Alexander Martinez-Armstrong into custody on suspicion of first-degree murder after police found the young boy unconscious and injured Saturday night, according to an APD news release.

The boy later died at the hospital from his injuries.

Martinez-Armstrong is not the victim’s father, according to the release.

Police responded to the call about an unconscious child at 10 p.m. Saturday in an apartment in the 14100 block of East Tennessee Avenue. The area is near the intersection of I-225 and Mississippi Avenue.

Aurora Fire Rescue paramedics tried to revive the 4-year-old boy, who was also found with “significant injuries,” but he died at a hospital from his injuries, the release said.

Police arrested Martinez-Armstrong, who admitted to hitting the child, after an on-scene investigation. He is in custody at the Arapahoe County Jail.

The investigation is ongoing and anyone with information is asked to call Metro Denver Crime Stoppers at 720-913-7867.

The Arapahoe County Coroner’s Office will release the child’s cause and manner of death pending an autopsy.