BOSTON (CBS) – The two men accused of dragging a man from a car for half-a-mile in Dorchester last week now face murder charges.

Dejon Barnes, 18, and 23-year-old Kenneth Ford were charged with unarmed robbery for dragging 18-year-old Kemoni Miller as he tried to sell them an iPhone for $600 on the night of November 16.

READ MORE: Coronavirus In Massachusetts: Today's Developments

Dejon Barnes (right) and Kenneth Ford (back left) are escorted to court by State Troopers, Nov. 19, 2018. (WBZ-TV)

The Suffolk County District Attorney’s Office said Friday that Miller died at Boston Medical Center Wednesday after four days on life support. Prosecutors then upgraded the charges to murder.

Miller, the father of a 1-year-old girl, met with Barnes and Ford, who were in a car on Gallivan Boulevard late last Friday night.

“From the passenger’s seat, Barnes allegedly took the phone and closed his window on Miller’s arm as Ford accelerated at a high rate of speed,” Suffolk County D.A. spokesman Jake Wark said in a statement Friday.

READ MORE: Wednesday's Child: 13-Year-Old Serenity

“Miller was dragged about half a mile and suffered a life-threatening head injury when he fell from the car. He was transported to Boston Medical Center but never regained consciousness.”

Kemoni Miller. (Family photo)

Wark said investigators identified Barnes as the one who had offered to buy the phone from Miller. State Police arrested both men at a party in the West End early Sunday morning.

Barnes and Ford were being held on $100,000 cash bail each on the robbery charges after their arraignment Monday.

MORE NEWS: Multiple Chances For Snow Over Next Several Days

Their arraignments on the murder charges have not been scheduled yet, but they are both due in court for a hearing on December 4.