Investigators with the Aiken Department of Public Safety are working to solve an equation.

Rather than writing with chalk on a blackboard, though, they're writing with spray paint on a roadway to piece together the deadly formula that has far-reaching consequences for the people involved.

On Tuesday, the accident reconstruction team returned to the scene of a deadly incident on York Street, where two pedestrians were struck by an SUV while walking down the sidewalk on Saturday.

Lukisha Nicole Thomas, 29, of Aiken, was walking with a man, Ray Charles Wooden Jr., when they were struck while walking south on the sidewalk on the 800 block of York Street about 2 p.m. on Saturday, police have said.

The 2006 Jeep, driven by Aiken attorney Thomas G. Woodruff Jr., left the roadway and struck Thomas and Wooden, investigators have said. Thomas and Wooden were taken to Georgia Regents Medical Center, where Thomas later died in surgery. Wooden was last reported in stable condition on Sunday.

Thomas' 2-year-old son was with her when the accident happened. He was examined at Aiken Regional Medical Centers and released.

After the accident on Saturday, investigators with Aiken Public Safety's accident reconstruction team were on the scene gathering and making note of evidence. They returned to the scene on Tuesday morning.

The team was gathering data at the scene to put together a scale drawing of the accident scene.

“We have surveying equipment out here,” said Sgt. Chris Hammell. “We'll be recording, just like someone surveying a piece of land. We'll be collecting the data to be able to draw the road and the exact location of these evidence points where you see the orange paint on the ground.”

Lines and circles drawn around the scene in orange spray paint were put down by investigators on Saturday to make note of evidence, such as skid marks where the vehicle reportedly left the roadway, and where the victims were standing when they were struck.

Hammell said it's normal for the team to go to a site a second time.

“Evidence can get washed away and destroyed with time. Skid marks start fading the second they're made,” he said.

The objective of the first day on an accident scene is to preserve that evidence, he said.

“We come out to the scene and do things such as taking pictures of everything as it was that day, putting marks and paint on the ground to preserve where it was that day, so we can come back on another day and do our actual investigation,” he said.

Once the data has been obtained, it's time to put it together.

“They'll use that data to make a scale drawing, which we can use in equations and calculations in trying to determine things such as cause, energy and speed involved in the collision,” Hammell said. “We use calculus, algebra, physics – all that stuff you thought you'd never use again. Whoever thought a police officer would use that stuff?”

The team responds to any traffic fatality, and accidents with serious injury, according to Hammell, who added that the team responds to a “handful” of incidents per year.

“We also respond to any collisions with an undetermined cause,” he said. “A general patrol officer who has just basic police investigation skills may not be able to determine what happened. We bring out a team who has advanced collision investigation training to help determine the cause.”

Officers on the accident reconstruction team must go through special training at the state S.C. Criminal Justice Academy, which offers three levels of collision reconstruction, Hammell said. Each class is 80 hours and lasts two weeks.

“Our team members have all been through those three classes, so that's 240 hours worth of training there,” he said.

From there, officers can go into specialty training.

“They take classes specifically in things such as investigating collisions with motorcycles – a different vehicle with different dynamics and physics to it,” Hammell said. Other classes focus on collisions involving pedestrians and bicyclists.

The team's report from Saturday's deadly accident could take two or three weeks to compile, at which point it will be taken to the Solicitor's Office to discuss what charges, if any, will be appropriate.

Teddy Kulmala covers the crime beat for the Aiken Standard. He is a graduate of Clemson University and hails from Williston.