THE BRONX - A Bronx cab driver has pleaded not guilty to causing his girlfriend's car to crash and then stabbing her to death.

Dionis Espinal stared at the ground during his arraignment at the Bronx Criminal Courthouse on a number of charges, including murder, criminal possession of a weapon and criminal contempt. No family members of his were present.

The 30-year-old was arrested Wednesday after investigators say he went after the young mother of his own 1-month-old baby. Police say 20-year-old Katherine German received a text Wednesday morning from an unknown male, saying that Espinal was at the Paradise Motel with someone else.

Police say German went looking for Espinal with a friend. After they made contact, she left the motel with her friend in a SUV. Espinal followed in his green taxi leading to a high-speed chase on the Pelham Parkway.

Espinal allegedly sideswiped German's Honda Pilot with his taxi, causing it to flip over.

Authorities say he approached the overturned car and proceeded to stab the young mother repeatedly. Espinal also confronted the driver of the vehicle, cops say, punching him in the face with a set of brass knuckles.

A medical examiner has determined that German was not killed by the crash, but by the multiple stab wounds she suffered to her head and neck.

Espinal's lawyers say that he doesn't have a criminal record, but German did get an order of protection against him in May. German's mother claims Espinal hit his girlfriend at least once, even while she was pregnant.

Espinal is being held without bail and is due back in court Sept. 3.