The Brooklyn mother accused of drowning her three children in the waters off of Coney Island earlier this week was arraigned on murder charges Friday morning, authorities said.

Erin Merdy, 30, was arraigned on seven counts of murder, including murder in the first degree, according to a criminal complaint filed with the Brooklyn District Attorney’s office.

The arraignment took place inside a room at NYU Langone Hospital in Brooklyn. Merdy has been undergoing psychiatric evaluation at the hospital since she was found on the Coney Island Beach boardwalk barefoot, wet and despondent on Sept. 12.

Surveillance footage captured Merdy walking on the beach toward the water with her three children — 7-year-old Zachary Merdy, 4-year-old Liliana Merdy and 3-month-old Oliver Bondarev — at 12:54 a.m. that day, the complaint says.

Emergency responders located the single mother at Brighton 6th Street and the Riegelmann Boardwalk after a concerned family member called 911 to report that she may have harmed her children, police said.

All three children were found unconscious on the shoreline near West 35th Street at approximately 4:20 a.m., according to police. They were pronounced dead at NYC Health + Hospitals/Coney Island, the NYPD said.

The city’s medical examiner ruled all three deaths homicides by drowning. After she was taken into custody, Merdy told police she had hurt her children and that they were “gone,” according to the criminal complaint.

Mourners held a vigil for the three children on Thursday.

Merdy's next court appearance is set to take place on Sept. 20, the DA’s office said. NY1 has reached out to her attorney for comment.

NY1 journalist Nia Clark contributed reporting.