11-month-old Halo Blanton, inset, was the subject of an Amber Alert in upstate New York on Sunday morning. Cops found her Sunday afternoon in a pipe access area filled with mud and water in Schenectady, New York. Her mother, Persia Nelson, seen in the white T-shirt talking to her lawyer, was arrested on a manslaughter charge. (Halo: New York State Police; Screenshot: WRGB/YouTube)

A 24-year-old New York mother is facing murder and manslaughter charges in the death of her 11-month-old girl after she allegedly dumped her down a 10-foot pipe access area with mud and water at the bottom and left her there “to essentially die.”

Persia Nelson pleaded not guilty to the manslaughter charge on Monday morning in Schenectady City Court. Police added a murder charge Monday afternoon after an autopsy revealed her daughter, Halo Branton, died of hypothermia, according to the Albany Times-Union. Halo was the subject of an Amber Alert issued shortly after 10 a.m. Sunday. The alert said she had been last seen near 12th Street at Campbell Avenue in Schenectady around 9:30 p.m. Saturday.

Authorities from Schenectady police, New York State Police and the FBI, among others, searched the area. Cops tragically found the girl around 1 p.m. Sunday on the campus of General Electric. Paramedics rushed the girl to the hospital where doctors pronounced her dead, Schenectady police Lt. Ryan Macherone told reporters. A criminal complaint obtained by Law&Crime said the girl died after Nelson dropped her down a 10-foot deep “pipe access area” filled with water and mud at the bottom, which was located on the General Electric campus, about 3 miles from where Halo was reported missing.

Cops took Nelson into custody on Sunday morning.

Local CBS affiliate WRGB posted a video on YouTube of Monday’s 10-minute arraignment on the manslaughter charge. A prosecutor with the Schenectady County District Attorney’s Office said Nelson dumped the baby down the pipe access area and “left the child there to essentially die.”

A judge set Nelson’s bail at $500,000 cash and $1 million bond, records show. Prosecutors said Nelson could be a flight risk as she has no job and moved to the area in November to live with a boyfriend. She has a second child that she does not have custody of and has “limited contact with,” prosecutors say.

A cousin of the girl’s father told the Albany Times-Union her family is devastated. The father had been fighting for custody, the cousin said.

“She was beautiful, she was charming, she was very intelligent,” she told the newspaper. “She looked just like her father.”

Macherone declined to say who reported the girl missing. New York State Police when announcing the Amber Alert said Halo was “taken under circumstances that lead police to believe that they are in imminent danger of serious harm and/or death.” The agency originally said the girl was found safe and unharmed after canceling the alert. However, it has since edited its posts on social media to say “Halo has been located.”

Nelson’s next court date is scheduled for Thursday.