Pedro Jones, 22, who was arrested in August 2010 after beating his girlfriend's son to death, pleaded guilty to second-degree murder Wednesday.

He will serve 16 years to life in prison, under the plea deal, according to Robert Clifford, the spokesman for Suffolk County District Attorney Thomas Spota. Sentencing is scheduled for Feb. 14 before Judge James Hudson.

New York State police said Jones, 20 years old at the time, was babysitting the boy. According to court documents, Jones told state troopers, "I was trying to make him act like a boy instead of a little girl," and admitted to hitting him in the past too.

Jones lived with the boy and boy's mother on the Shinnecock Indian Reservation in Southampton; Jones is not Shinnecock.

State police said they were called to Old Point Road East on Aug. 1, 2010 at about 8:25 p.m. for a child in cardiac arrest. The 16-month-old was taken via ambulance to Southampton Hospital, where he was pronounced dead at 9:11 p.m. The New York State Police Bureau of Criminal Investigation in conjunction with the Suffolk County District Attorney's Office opened a homicide investigation, and arrested Jones.

While the investigation was still ongoing, Jones was initially charged with first-degree manslaughter. He was indicted by a grand jury on charges of murder and endangering the welfare of a child days later.