EDISON — A man and woman from South Carolina have been arrested and charged in connection to a Dec. 20 fatal robbery at a township gas station.

Marcus A. Wright, 22, of Beaufort, South Carolina, was arrested Thursday on charges of first-degree murder, first-degree armed robbery, second-degree conspiracy to commit armed robbery and a second-degree weapons offense.

Olya Quinnam, 22, was charged with second-degree conspiracy to commit armed robbery and hindering apprehension.

A masked gunman robbed the Speedway Gas Station during the early morning hours. After getting the cash, the robber fired a single shot, killing 38-year-old John Bertram, a resident of the Fords section of Woodbridge.

Surveillance photo of gunman at Speedway gas station in Edison (Middlesex County Prosecutor's Office)

Investigators say Quinnam waited outside while Wright robbed the store.

Middlesex County prosecutors did not say Thursday how the suspects were identified or tracked down.

Both remain in South Carolina awaiting extradition proceedings.