Truck computer contains clues to motive in murder, prosecutors say

▶ Watch Video: Sneak peek: The Hit-and-Run Homicide of Davis McClendon

When authorities in Greenwood, South Carolina, arrived at the deserted intersection after 1 a.m. on May 7, 2023, they found a mangled BMW sedan in the road with debris scattered around it. On the shoulder near the woods, lay the car’s fatally injured owner, 46-year-old Davis McClendon. But something about the scene seemed strange.

McClendon was about 50 feet away from his car, suggesting he’d been outside standing next to it and been hit. His shirt and shoe were lying on the pavement. There was no other vehicle with relevant damage.

McClendon’s girlfriend, Meredith Haynie, was there by the time authorities appeared, but she said she hadn’t been there to see the collision. Authorities would use an array of evidence to build a murder case against Haynie’s soon-to-be-ex-husband Bud Ackerman, who would claim hitting McClendon with his truck had been an accident. But prosecutors argued the touch screen computer in the dashboard of Ackerman’s Ford F-250 pickup truck provided a blueprint of the intent they needed to prove he’d been targeting McClendon that night — and killed him with “malice aforethought.” 

Haynie tells “48 Hours” correspondent Anne Marie Green she’d been on a date with McClendon that night, before he’d vanished out of a local club at 12:51 a.m. Haynie’s only TV interview is featured in “The Hit-and-Run Homicide of Davis McClendon.” An encore of the broadcast airs Saturday, August 22 at 10/9c on CBS and streaming on Paramount+.

Haynie told authorities she and McClendon had begun the evening at a restaurant called Break on the Lake. Next, they’d gone to a party and then to a well-known club called Key West. When McClendon suddenly left out the back door, she said she had suspected he was going to meet Ackerman, who had been critical of her and McClendon for seeing each other before Ackerman’s and Haynie’s divorce was final. She said Ackerman had been compulsively calling her that night. And she allowed investigators access to her phone, which turned out to contain texts supporting her account.

“What did the text messages reveal?” Green asked lead detective Lt. Matthew Womack of the Greenwood County Sheriff’s Office. 

“It showed the pattern of what she was explaining to the on-scene investigators,” Womack replied. “Like him calling multiple times, him texting multiple times, things of that nature.”    

Within minutes of arriving at the scene of the crash, authorities suspected Ackerman had run McClendon down. There was an oil trail leading from the crash site directly to the house where Ackerman was living. And evidence suggested Ackerman’s pickup sideswiped the sedan, hitting McClendon next to the driver’s door, carrying him across the road and depositing his body where it was found.

Having heard Haynie’s story, investigators hoped they could get more information from Ackerman himself. They soon located him at his parents’ home about a half mile from the crash site and they found his pickup truck leaking oil in the driveway. But when they tried to question him, Ackerman referred them to his attorney.

In the coming days, investigators would retrieve time-stamped video showing Ackerman at the locations where Haynie and McClendon had spent their evening out and soon afterward, near the crash site itself. But Ackerman still wasn’t talking much to them.

That’s when his truck started speaking for him.

Womack says the touch screen computers or “infotainment systems” in many modern cars measure and store incredibly detailed information about how, when and where the vehicle is being operated. And Ackerman’s pickup truck was no exception. When authorities extracted data from the onboard computer, they found a motherlode of incriminating measurements.

“… In a 24-hour time period, it’s over 3,000 events …” Womack told Green. “And then each one is time-stamped … for each event.”

He says Ackerman’s “infotainment system” logged a series of communications almost like  digital “handshakes,” in which the truck automatically pinged public Wi-Fi systems it happened to pass.

“…Let’s just say there was … a fast-food restaurant … and the device will do what we call a handshake with that,” Womack explained. “Essentially the fast-food restaurant will say, hey … your device can connect to me and … the vehicle says, I see you …” 

By plotting the locations of the truck’s digital handshakes and using other data from that night, authorities were able to establish a route Ackerman had traveled. It showed that over the course of the evening, he’d driven past the Key West Club, Haynie’s house, Break on the Lake restaurant, and onto McClendon’s street. Data also showed Ackerman’s truck had been near the scene of the collision when it occurred.

And that’s not all. Womack told “48 Hours” the pickup also stored performance information, including measurements like speed and acceleration.

“It told you … speed, um, it told you the braking. Whenever he shifts the gears, when he opens the door, when he connects his phone, when he disconnects his phone … I mean, it tells you a lot of information.”

Experts would determine that seconds before the impact, Ackerman was driving about 25 miles per hour on the dark road. It was in his neighborhood, so it’s likely he would have known it was a dead end. At precisely 1:11:33 a.m., the data showed a “wheel slip,” in which acceleration or braking caused the tires to lose contact with the road.

“… We could narrow it down to tenths of seconds when the collision occurred,” Womack said, adding that data show seconds later, Ackerman’s truck had stopped. “… Bud’s opening the door to his vehicle, um then … he shifts it to park.”

Womack said Ackerman then got out of the truck.

“… Then he gets back in and then it’s shifted to drive,” Womack continued, adding that minutes later, Ackerman’s truck stops again and his phone disconnects from the vehicle’s computer. “That’s when he got home and got out,” Womack said. 

“And took his phone with him?” asked Green. 

“And took his phone with him. That’s correct,” Womack replied.

Bud Ackerman had been arrested within hours after the collision, but his attorney Jack Swerling says much of the authorities’ narrative of that night is not correct.

Swerling acknowledged Ackerman was unhappy his wife had begun dating before the divorce was final and even that Ackerman hit McClendon and his BMW that night. But he says his client was meeting with McClendon merely to speak with him. According to Swerling, McClendon was standing further out toward the center of the road than prosecutors contend. And it was too dark for Ackerman to see him before the last few moments. Swerling says hitting McClendon was an accident, in fact arguing Ackerman aimed for McClendon’s empty car to stop the truck’s forward momentum.

“… He’s trying to avoid hitting him,” Swerling said.

After a seven-day trial last fall, a jury disagreed, convicting Bud Ackerman of murdering Davis McClendon. The judge sentenced Ackerman to 45 years in prison.