WILLINGBORO, N.J. (CBS) – Police have charged Terrance Matthews in the killing of his ex-girlfriend’s grandmother and 9-year-old brother in Willingboro. Before his arrest on Thursday afternoon, Matthews led Camden County Police on a high-speed chase while live-streaming on Facebook until he crashed his car into a pole.

The Burlington County Prosecutor’s Office announced that 23-year-old Matthews has been charged with two counts of murder, one count of kidnapping and other charges after killing 68-year-old Jennifer Vassell and her grandson 9-year-old Ishon Mathiln Jr. on Wednesday evening.

Police were dispatched to the Wawa store on Springside Road for a report of a woman in distress just after 10 a.m. on Thursday. When Matthews’ ex-girlfriend told an employee that Matthews had killed her family, he fled the store.

Both victims were found around 2 p.m. Thursday, with multiple stab wounds and Ishon appears to have been drowned in a bathtub inside a house on the 100 block of Eastbrook Lane.

Investigators say Matthews murdered the victims on Wednesday evening while his ex-girlfriend was at work and when she returned, he held her hostage throughout the night. Prosecutors believe the motive for the murders stems from an argument Matthews had with his ex-girlfriend earlier in the day.

Matthews then apparently thought it was a good idea to stream his Camden County police pursuit live on Facebook Thursday afternoon.

Moments after he unbuckled his seatbelt, he crashed his white Toyota Scion.

“I saw guns drawn and a guy running down the street,” a witness said.

Camden County spokesperson Dan Keashon says Matthews then assaulted an officer before being arrested by police.

“Ran into a neighbor’s yard, apprehended him. They tased him twice,” the witness said.

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“My heart goes out to them, my prayers go out to them. The whole idea that this life and their lives have been snuffed out, I mean words can’t begin to speak to that,” neighbor Titus Welcome said.

Police taped off an entire section of the neighborhood. Detectives collected evidence from inside the home as those living nearby returned home from work to find the large crime scene.