IRVING, Texas -- A second person has been arrested in the murder of a Dallas teen hours after he had graduated from Carter High School.

Courtney Wright was arrested and charged with murder a few days after 17-year-old Jeremiah Robinson was taken into custody for the same charge.

<p>Jeremiah Robinson</p>

The two are accused of shooting and killing 18-year-old LD Cox after a verbal exchange at an Irving gas station between two groups of friends.

A witness says he and Cox shook hands to try and deescalate the argument at 7-Eleven before the groups left in separate cars.

He told police he was in the backseat and Courtney Wright was driving, while Robinson was in the front seat.

The witness said Wright followed the car carrying Cox and his friends, then Robinson rolled down his window along West Walnut Hill Road and fired several shots into the car.

Cox was shot in the head and chest and died at Parkland Hospital in Dallas a few hours later.

The teen was a wide receiver and an All-State track standout at Carter High, where he was also named Homecoming King.

Hundreds turned out for a vigil to remember him on Monday night.

A celebration of life will be held for Cox at Friendship-West Baptist Church on Saturday, June 3 at 12 p.m.