How a Can of Red Bull Led to an Arrest for a Drunk Driving Death

When Dr. Caroline Muirhead of Glasgow, Scotland, started dating her new boyfriend, Alexander McKellar, in the fall of 2020, she didn’t notice any red flags. They’d met on Tinder, the relationship was progressing well and they quickly got engaged.

But one night, Muirhead’s new fiancé confessed something that made the forensic pathologist’s stomach turn.

Muirhead told the media that McKellar sometimes became erratic when he drank, and she could tell by his reaction to a police car driving past them one night in November 2020 that he was perturbed by the authorities. Sensing there was a story behind his suddenly tense demeanor, she decided to ask him about his past. “I said if we were going to be together and be a team, he needed to tell me what was wrong and I’d support him,” she told Scotland’s Daily Record.

McKellar ordered Muirhead out of the car and turned off her phone, stashing it in the glove box. He told Muirhead that three years earlier, on September 29, 2017, he’d hit a cyclist while he was driving drunk through the Scottish Highlands with his twin brother Robert in the passenger seat. Instead of seeking out medical help for the bicyclist, Tony Parsons, McKellar, then 25, drove away, leaving Parsons, a 63-year-old grandfather, to die.

It was later determined that, after the collision, Parsons, a former naval officer, had suffered catastrophic pelvic, rib and spine fractures. He had been participating in a 100-mile charity bike ride from Fort William back to his hometown of Tillicoultry to raise money for a prostate cancer charity; it was an illness for which he’d previously been treated.

McKellar recruited his brother to help him conceal the crime, and the duo buried Parsons’ body in a shallow grave within the remote Auch Estate, where the two lived and worked as farmhands.

“He started having a panic attack. He was gasping and started wailing,” Muirhead said about the moment when McKellar first told her about Parsons’ killing. “…I was in shock, frozen almost. I didn’t know what to believe. This man I thought I could be with for the rest of my life had just told me he was a killer. I didn’t know what to do.”

Immediately following the confession, McKellar offered to drive Muirhead to the burial site, and she took him up on the offer. After parking the car, she followed him on foot for about 15 minutes before he pointed out where the body was buried: in a pit where animal carcasses were typically dumped.

“He told me what had happened and how they [the brothers] had hit him, that it was an accident,” Muirhead told the Daily Record. He reportedly told her they hadn’t called police because they didn’t trust authorities and believed the cops were “out to get them.”

Criminal psychologist Dr. Jameca Woody Cooper tells A&E Crime + Investigation that the act of concealing a crime as McKellar did—for as long as McKellar did—requires a unique type of “strict mental separation.”

“The offender holds two conflicting self-views, being a ‘law-abiding citizen’ and someone who caused a death without feeling conscious conflict. But over months or years, the mental effort needed to hide signs of guilt, such as intrusive thoughts, slip-ups in speech or avoidance, drains their mental resources,” Cooper says. “McKellar's confession was prompted by his fiancée's demand for honesty about past behaviors; the idea of her uncovering the truth later generated unbearable anticipatory guilt.”

After hearing his confession, Muirhead reported McKellar to police and went undercover to begin quietly collecting evidence to aid the authorities’ investigation. In December 2020, she secretly marked Parsons’ burial spot with a crushed Red Bull can so authorities could locate his body, leading to both twins’ arrest one year later.

“This quick thinking by Caroline allowed Tony Parsons’ family to not only finally find out what happened to him, but to be able to lay him to rest,” Dawn Young, who covered the case on her podcast, Scottish Murders, tells A&E Crime + Investigation.

Alexander initially faced a murder charge, but it was reduced to culpable homicide after he entered a guilty plea, resulting in a 12-year sentence.

Robert admitted to trying to defeat the ends of justice and received a prison term of five years and three months in August 2023.

Young says the case still sticks with her because of what Parsons endured in his final moments: “Tony was still alive, would have likely had some awareness of what was happening, that these men were not going to be helping him. What must have been going through his mind in his last moments really got to me. Tony was doing absolutely no harm to anyone; he was cycling for a charity. Alexander and Robert McKellar should not have been on the road that night.”

In 2025, the Parsons family won a six-figure settlement in the case. The compensation claim was filed against McKellar and was covered by the insurance provider for the vehicle McKellar drove when he killed Parsons. The matter was resolved privately, and the specific amount of the settlement was not made public.

Muirhead moved on from her relationship with McKellar and found love again with someone new.