The incident started around 9 p.m. near the Wake-Johnston County line.
State Highway Patrol Sgt. Jeff Gordon told ABC11 that a tractor-trailer cab lost control on the snow-covered highway, spun out, and then came to rest across the roadway.
The slick conditions caused two other vehicles to go down an embankment. Another tractor-trailer, driven by 39-year-old Larry Kepley of Winston-Salem, then pulled over on the right-hand shoulder to help.
The Good Samaritan was trying to setting out reflectors to help the tractor-trailer driver when Gordon said a red Volvo came along and struck Keply and one of the drivers who went down the embankment, 34-year-old Nathaniel Williams.
Williams was a member of the U.S. Navy who was stationed at Fort Bragg for special training. He was living in Hope Mills.
Gordon said the Volvo then fled the scene.
Kepley died at the scene, while Williams was taken to WakeMed in critical condition - where he later died. Williams had just returned from a year-long deployment in Afghanistan last month.
Raleigh police later found the Volvo on Lake Wheeler Road and took 21-year-old Marshall Hudson Doran, of Kure Beach, into custody. Troopers say Doran was driving under the influence and had illegal drugs in his possession at the time of the crash.
Doran was originally charged with two counts of second-degree murder. A magistrate set his bond at $5 million. The charge was later lowered to felony death by a motor vehicle, and his bond was reduced to $500,000.
Meanwhile, a friend saw Williams right before he was killed.
"I thought about the commercial that talks about you go and you fight in a war and come back and you're killed on American soil by a drunk driver and that was a flash," said Mildred Hawthorne, Williams' friend. "This is kind of what happened. He's helping someone else."
Doran is being held at the Wake County Detention Center.