NEW YORK (CBSNewYork) – A suspect has pleaded guilty in the stabbing death of Barnard College freshman Tessa Majors last December in Morningside Park.

The 13-year-old pleaded guilty to first-degree robbery Wednesday in Manhattan family court.

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He will be sentenced in two weeks and is expected to receive 18 months detention.

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Two other teens – both 14 years old – face murder and robbery charges and are being tried as adults.

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Majors, 18, was killed on Dec. 11 as she walked through the park not far from campus.