The 30-year-old woman, believed to be the mother of the 7-year-old boy, 4-year-old girl and 3-and-a-half-month-old girl, is being questioned at a local police precinct, Chief of Department Kenneth Corey said Monday morning in a news conference.
She is not in custody, and the investigation remains “very active,” he said.
There is no indication of prior neglect or abuse, Corey said, citing preliminary information.
“We don’t know exactly what happened here,” he said, stressing the information he provided was preliminary.
Police got a 911 call at 1:40 a.m. from someone concerned a family member might have harmed her three children, Corey told reporters. Officers went to the apartment but got no response.
A man who identified himself as the father of one of the children met officers in the building and told them he shared the caller’s concerns. He told police he believed the woman and children were at the boardwalk in Coney Island, Corey said.
Officers began searching for the woman and children, canvassing the boardwalk, the beach, surrounding streets and the local hospital.
The search went on for about 90 minutes, Corey said, until another 911 call directed officers to Brighton 6th Street and Riegelmann Boardwalk in nearby Brighton Beach, where they found the woman and other family members. That call was regarding a despondent woman, a police spokesperson told CNN.
The woman authorities found was “soaking wet,” Corey said, though it was unclear if she’d been in the rain or in the water off the coast.
The children were not with her, and the search continued with ground, aviation and harbor units until 4:42 a.m., when officers found the children on the shoreline at West 35th Street in Coney Island, about two miles from where the woman was found.
Officers immediately started CPR on the children before they were taken to Coney Island Hospital and pronounced dead, Corey said.
CNN’s Liam Reilly contributed to this report.