The first thing he did was google his target. It only took a few seconds to find a number of postings that referenced the lieutenant. He clicked on images and printed off a couple of colour headshots. Next, he opened the glass door of his Labcold vaccine fridge, which contained a selection of colour-coded ampoules. He knew exactly which two he needed for the job. He selected midazolam and propofol, which he planned to combine to create his own customised lethal cocktail. Both drugs were powerful sedatives used by anaesthetists prior to surgery. Wicks’s unique concoction was capable of knocking out a giant gorilla in less than three seconds. Once his subject was unconscious, he would administer two more doses. The recipient would never wake up.

He returned to his computer and sent a brief email to his cousin, a part-time waiter and shelf stacker, who doubled as a driver for him when circumstances dictated.

Be at mine with the Cherokee by 2.30. It’s a last-minute job, so I’m paying double rates.

Finally, he opened his small wall safe and took out a large bundle of fifty-dollar bills. He counted out two thousand dollars and placed the notes in a white envelope. He was ready to go to work.

Franklin’s private jet touched down at Sky Harbor International Airport in Phoenix just after five in the evening, where a chauffeur-driven Mercedes S-Class was waiting to meet him on the airstrip. The Convention Center was just a three-mile drive away and, as the blacked-out limo passed the front of the building, Franklin saw a large crowd queuing down the street, waiting to be admitted.

He was dropped at the rear entrance where he was met by one of his son’s staffers, who gave him an all-access lanyard and escorted him through to the backstage lounge area. He immediately spotted John, deep in conversation with his campaign chief, Cathy Douglas. He made his way across the busy room and greeted the pair, double kissing Cathy and embracing his son.

“Looks like a huge crowd tonight. How’s the speech going, John?”

“All good, Dad. Where do you want to watch it from? There’s a VIP box on the first level or the live feed will be shown in here.”

As ever with his father, John knew you could never second-guess him. “Neither. I’ll pace nervously around in the wings.”

Cathy laughed on cue. “Richard, I’ll sort you out a table with some snacks and a bottle of Jim Beam.”

“Sounds perfect, Cathy, thank you. John, I’ll see you afterwards. We need to catch up on some stuff. Now get out there and kill ’em.”

The Convention hall was rammed to the rafters. Three thousand fervent Republican supporters screamed and applauded and waved their giant placards as John Franklin ran through his carefully rehearsed set piece. As ever, his charismatic personality and clichéd sound bites wound the audience up into a near frenzy.