Cortoglia is a picturesque town in the heart of Italy’s Campania region. It rests high on a hill, 40 miles north of Naples, with commanding views towards Monte Taburno to the east, and Vesuvius to the south, and has been described, quite simply, as “Heaven on Earth”.The population of the town is 1,463 and hasn’t varied greatly for over a century.

The town’s income is derived from three main sources: wine, olive oil and truffles.The Cortoglia White, aromatic with a vibrant acidity, is one of the most sought-after wines on Earth, sold out long before it’s bottled.

As for the olive oil, the only reason you never see a bottle in your local supermarket is because many of the leading Michelin starred restaurants won’t consider allowing any other brand on their premises.

The bonus, which allows the locals to enjoy a standard of living envied by their neighbours, is their truffles. Restaurateurs travel from all corners of the globe in search of the Cortoglia truffle.

It’s true some people have been known to leave Cortoglia and seek their fortunes further afield, but the more sensible among them return fairly quickly. The town boasts only half a dozen shops and a restaurant. The council wouldn’t sanction any more for fear it might attract tourists.

There is no train service, and a bus appears once a week for those foolish enough to wish to travel to Naples.The town is run by the Consiglio Comunale, made up of six elders. The most junior member, whose lineage only goes back three generations, is not considered by all to be a local.

The mayor, Salvatore Farinelli, his son Lorenzo Farinelli, Mario Pellegrino, the manager of the olive oil company, Paolo Carrafini, the owner of the winery, and Pietro De Rosa, the truffle master, are all automatically members of the council.

The one remaining place comes up for election every five years. As no one had stood against Umberto Cattaneo, the local butcher, for the past 15 years, voters had almost forgotten how to conduct an election.

The Polizia Locale had consisted of a single officer, Luca Gentile, whose authority derived from the city of Naples, and Luca tried not to disturb them unnecessarily. This story concerns the one occasion it was necessary.

No one could be certain where Dino Lombardi had come from but, like a black cloud, he appeared overnight, and was clearly more interested in thunderstorms than showers. With the build of a heavyweight boxer who didn’t expect his bouts to last for more than a couple of rounds, he began his reign of terror with the weaker inhabitants of the town.

He persuaded the shopkeepers, the local tradesmen and the restaurateur they needed protection, even if they couldn’t be sure from whom as there hadn’t been a serious crime in Cortoglia in living memory.

To be fair, Constable Gentile was due to retire in a few months’ time at the age of 65 and the council hadn’t got round to finding his replacement. But a further problem arose when Salvatore Farinelli the mayor died at the age of 102, and an election had to be held to replace him. It was assumed that his son Lorenzo would succeed him.

That was until Lombardi turned up at the town hall, and entered his name on the list for mayor.

Still, no one doubted Lorenzo Farinelli would win by a landslide, so it came as something of a surprise when the town clerk, on crutches, his left leg in plaster, announced that Lombardi had polled 511 votes, to Farinelli’s 486.

There was a gasp of disbelief from the crowd, not least because no one knew anyone who had voted for Lombardi. However, he immediately took over the town hall, occupied the mayor’s residence, and dismissed the council.

He’d only been in office for a few days when the citizens were informed he would be imposing a sales tax on all three of the town’s main companies, which was later extended to the shopkeepers and the restaurateur.

And if that wasn’t enough, he began to demand a kickback from buyers as well as sellers. Within a year, Heaven on Earth had been turned into Hell on Earth. So, frankly, it didn’t come as a surprise to anyone when Lombardi was murdered, shortly before Christmas.

Constable Gentile told the council the murder was out of his league, so he would have to inform the authorities in Naples. He admitted there were 1,462 suspects, and he had no idea who had committed the crime. Naples, a city that knows a thing or two about murder, sent one of its brightest young detectives to investigate the crime, to find and arrest the culprit.

Antonio Rossetti, who at the tender age of 32 had recently been promoted to lieutenant, was assigned the case.

He was already aware of Lombardi’s past record; extortion, bribery and corruption were but a few of his crimes. He assured his chief of police that he would wrap up the case as quickly as possible and be home for Christmas.

However, it didn’t help that Luca Gentile had disappeared. Some suggested he was suffering from the strain as the last murder in the town had been in 1846, when his great-great-great-grandfather had been town constable.

Either way, Gentile was the only other person who knew how the mayor had been killed. Lombardi had been cremated, and his ashes scattered within hours of his death.

“So you, Gentile and the coroner are the only people who know how the murder was committed,” the chief of police in Naples told his young lieutenant as he handed over the results of the autopsy.

“And the murderer,” Rossetti reminded him tartly.

Antonio arrived in Cortoglia later that morning and set up office in the local police station, which consisted of one small room, one unoccupied cell and a lavatory. He took the relevant case files out of his bag and placed them on the desk. He looked at the large, empty board on the wall and pinned a photograph of Lombardi in the centre.

He then decided to roam around the town – where council workmen were putting up bunting and raising a huge Christmas tree in the public square – in the hope that someone might approach him to supply information.

But even though he walked slowly, and smiled a lot, people crossed the road when they saw him as if he had some contagious disease. After a fruitless morning, Antonio returned to his office and made a list of those people who had most to gain from Lombardi’s death and came to the conclusion that he would have to start with the members of the Consiglio Comunale.

He wrote Wine, Olive Oil and Truffles on his notepad and took the photographs of the five councillors from the case file, and pinned them around Lombardi’s picture.

He decided to start with Truffles. He called at Signor De Rosa’s office later that afternoon.

“So how can I help you?” asked Signor De Rosa “I was rather hoping you might be able to shed some light on who killed Dino Lombardi?” said Antonio.

“I most certainly can. You need look no further, Lieutenant, because I killed Lombardi.”

Antonio was taken by surprise, but delighted to have a confession on his first day. He was already thinking about packing and returning to Naples in time to celebrate Christmas with his family.

“You do realise, Signor De Rosa, that if you confess to the murder, I will have no choice but to arrest you, and take you to Naples, where you will stand trial, and could spend the rest of your life in the prison at Poggioreale?”

“I have thought of little else since the day I murdered the bastard. But I can’t complain, I’ve had a good life.”

“Why did you kill Lombardi?” asked Antonio, who accepted that motive almost always accounted for any crime.

“Dino Lombardi was an evil and ruthless man, Lieutenant, who preyed on everyone he came into contact with. If he had been allowed to continue for much longer, he would have put us all out of business. Last year my little company made a loss for the first time in 300 years. So I took it upon myself to rid my fellow citizens of the fiend.”

He smiled. “I hear the council is planning to build a statue of me in the town square.”

“I only have one more question,” the detective said, looking up from his notebook. “How did you kill Lombardi?” “I stabbed him with my truffle knife,” said De Rosa without hesitation. “It seemed appropriate at the time.”

Antonio stopped writing and closed his notebook. “I feel sure you know, Signor De Rosa, that it’s a serious crime to waste police time.”

“Of course I do, Lieutenant,’ said De Rosa. “But now I have confessed, you can arrest me, drag me off to Naples and throw me in jail.”

“Which I would be only too happy to do, signor,” said Antonio, “if only Lombardi had been stabbed.”

The truffle master shrugged his shoulders. “Does it really matter? Just tell me how Lombardi was killed and I’ll confess to the crime.”

This was the first time Antonio had ever known someone admit to a crime they hadn’t committed. “I’m going to leave, signor, before you get yourself into even more trouble,” he said.

The truffle master looked disappointed. Antonio closed his notepad, stood up, walked out of De Rosa’s shop and back into the square without another word. He was on his way back to the police station when he spotted a pharmacy and remembered he needed a bar of soap and some toothpaste.

A little bell above the door rang as he stepped inside. He stood by the counter for a few moments before a young woman came from the dispensary, where she had been stringing colourful lights across the drug cabinets, and said: “Good morning, Signor Rossetti, how can I help you?”

Hardened criminals from the back streets of Naples couldn’t silence Antonio Rossetti, but a chemist from Cortoglia managed it with one sentence. “I need a bar of soap,” he eventually managed.

“You’ll find a good selection behind you on the third shelf down, Lieutenant.”

“Is it that obvious that I’m a policeman?” said Antonio. “When you’re the only person in town that nobody knows, everyone knows you,” she said.

Antonio selected a bar of soap but ignored the toothpaste, because he wanted an excuse to return. He placed the soap on the counter and tried not to stare.

“Will there be anything else, signor?”

“No, thank you.” Antonio picked up the soap and headed for the door.

“Were you considering paying or don’t the police in Naples bother with anything quite so mundane?” she asked, suppressing a smile. “I’m so sorry,” said Antonio, quickly placing a note on the counter.

“Do call again if there is anything else I can help you with,” she said, passing him a small bag and his change.

“There is just one thing. You don’t, by any chance, happen to know who killed the mayor?’

“I thought Signor De Rosa had already confessed to murdering Lombardi, and assumed by now you would have arrested him and locked him up?”

Antonio frowned, left the shop without another word and made his way back to the police station.

• Exclusively adapted by Jeffrey Archer for the Daily Express from Who Killed The Mayor. His latest must-read thriller, Next In Line (HarperCollins, £22), featuring William Warwick, is out now. Lord Archer’s fee has been donated to Give A Book.