The new focus on the case led one of Hernadez's family members or a friend to alert police that they suspected Hernandez's involvement.
When confronted, New York Police Commissioner Ray Kelly said Hernandez quickly confessed, even expressing "remorse" and "relief."
Hernandez was taken into custody at his home in Maple Shade, N.J., on Wednesday morning where he lives with his wife and daughter. The apartment is rented by his wife, Rosemary Hernandez, who let her husband move in after he told her that he was dying of cancer.
"We never had a problem with him," Hernandez's brother-in-law, Jose Lopez, told KYW, a CBS station in Philadelphia. "There was never a problem. He was a normal person. Never gave any sign that he did something like that."
Police have named other suspects in the past, but none had ever been arrested or charged.