Abdulsalam Al-Zahrani pleaded guilty to First Degree Manslaughter in Broome County Court.
The plea followed the determination that Al-Zahrani was competent to stand trial for the murder of Dr Richard Antoun. Two mental health doctors made the evaluation at Mid Hudson Forensic Psychiatric Center.
Al-Zahrani, 48, is from Saudi Arabia and was graduate student at Binghamton University in Vestal.
Dr Richard Antoun was killed in his office on December 4, 2009.
Al-Zahrani says he walked into Dr. Antoun's office to show him a paper, and claims Antoun laughed at him in a mocking tone, which is when he remembered the role Antoun played in a "plot" against him.
That's when Al-Zahrani pulled out a knife and stabbed the professor about 11 times.
The plea agreement carries a prison sentence of 15 years and deportation.
"This was the best way to ensure that certainly in the United States he would never walk a free man again," said Broome County District Attorney, Gerald Mollen (D). "And hopefully never a free man upon deportation in Saudi Arabia."