Leonor O'Hara, 23, was charged with aggravated assault, making terroristic threats and weapons possession following the 7 a.m. incident at a home on Saddle River Road near Saddle River County Park, Police Chief Robert Kugler said.
The 23-year-old Morris County man was hospitalized with a cut on his finger "either through a defensive attempt to thwart off an attempted thrust of the knife or an attempt by the suspect to grab the knife from the suspect," Kugler said.
He "also had an additional superficial puncture wound to the chest sternum area, which is believed to be caused by the 5-inch folding pocket knife," he said.
The pair had been dating about six months and stayed overnight at a friend's home when the two "had a heated argument that led to the incident," the chief said.
O'Hara remained held in the Bergen County Jail pending a detention hearing. She was ordered not to have any contact with the victim.
Responders included local police, EMS and other supporting units -- among them, the Bergen County Sheriff's Bureau of Criminal Identification, which collected evidence.
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