NEW YORK — A Coney Island mother was indicted in the drowning deaths of her young children in a seaside triple homicide, the Brooklyn District Attorney’s office confirmed Tuesday.

Erin Merdy, 30, faces one count of first-degree murder and nine counts of second-degree murder in the chilling deaths in which she walked the children from their nearby apartment to their demise in the Atlantic Ocean, officials said. It was unclear when the suspect would be arraigned.

Merdy was arrested in the early morning hours of Sept. 12 after worried family members called 911 to report their concerns over her three missing children: 3-month-old Oliver, 4-year-old Liliana and 7-year-old Zachary.

“The babies are gone,” a disoriented Merdy told relatives after turning up alone, barefoot and wet while wrapped in a bathrobe on the boardwalk in neighboring Brighton Beach. A massive search in the darkness by authorities located the youngsters lying on the beach near the shoreline, with all three pronounced dead at a nearby hospital.

Merdy, who had a history of mental health issues dating to 2019, had recently admitted herself to the hospital with postpartum depression following the birth of Oliver in May, officials said. The kids were located after a frantic manhunt in the rain.

She was initially taken to the 60th Precinct before being transferred to a Brooklyn hospital for psychiatric evaluation. Two days later, she was charged with murdering the children. According to authorities, Merdy told police after her arrest of a dream in which she walked the children into the ocean waters.

When arraigned from her hospital bed at NYU Langone-Brooklyn hospital last week, Merdy wore a yellow hospital gown and answered questions with her eyes closed tight. Scores of relatives gathered for a wake last Friday shortly after her remote court appearance.