NEW BEDFORD, Mass. (AP) — Authorities say the death of a 4-month-old infant in New Bedford earlier this week is under investigation.

A spokesperson for the Bristol district attorney’s office tells The Standard-Times the child’s mother called 911 at around 2 p.m. Wednesday after noticing dark discoloration on the infant’s lips.

Police officers and paramedics responded and found the mother holding the infant and attempting chest compressions.

Authorities say the baby was taken to St. Luke’s Hospital, where he was pronounced dead.

The cause of death remains unknown and the investigation is ongoing. No additional information was made public.