State child welfare officials are investigating the death of a 5-month-old boy Sunday morning at his Fuller Park neighborhood home on the South Side.

Jacob Martin was discovered not breathing about 7:40 a.m. at his home in the 200 block of West 43rd Street, according to police and the Cook County medical examiner’s office.

He was taken to Mercy Hospital, where he was pronounced dead at 8:21 a.m., authorities said. An autopsy Monday was inconclusive pending further studies.

The state Department of Children and Family Services is investigating allegations of neglect against Jacob’s mother, agency spokeswoman Karen Hawkins said. The agency has not had prior contact with the family.

A sibling who was home at the time has been placed with a relative under a DCFS-monitored safety plan, Hawkins said.

Police could not say Monday afternoon whether the boy’s death appeared suspicious.

Area Central detectives are conducting a death investigation.