The town where Amanda Knox and Raffaele Sollecito await their fate is the home of Baci, but it's not all sweetness and light

Few other Italian cities would have made a more apt setting for the Meredith Kercher murder trial and appeal than this most idiosyncratic of central Italian hill towns.

Among Italians, Perugia is known, above all, as a stronghold of Freemasonry – a fact that a senior mason once put down to "400 years of pontifical domination" when the city formed part of the Papal States. During the unification of Italy in the 19th century, it was the scene of an infamous civilian massacre by the pope's Swiss mercenaries that is commemorated to this day.

There are more than 20 Masonic lodges in Perugia, with an estimated combined membership of almost 1,500 – remarkable figures for a city of 170,000 inhabitants. A prosecutor who launched an investigation into the city's Freemasons in the early 1990s claimed they had a grip on every aspect of civic life – a claim vehemently denied by Masonic representatives.

On the surface, Perugia is all sweetness and light. Literally so.

On fine days in spring and autumn, like those on which the final stages of the appeal have been held, Perugia's historic centre, 450 metres above the Tiber, is a dream of airy luminosity. And if the city is known for anything outside Italy more than for the trial of Amanda Knox and her former boyfriend, Raffaele Sollecito, it is for its chocolate. Perugia is famed in particular for the hazelnut-and-gianduia Baci ("kisses"), two of which Sollecito set before his lawyer, Donatella Donati, just before her final submission on his behalf.

Edible love tokens are an appropriate enough symbol for this city of young people, home to both its 14th-century university, where Sollecito studied, and the University for Foreigners, attended by Knox and Kercher. In a country with one of the world's lowest birth rates and a rapidly ageing population, it comes as a shock to see the cathedral square packed with people in their 20s on any term-time evening.

But when winter draws in, as it will do soon, and mist begins to swirl up from the river valley through the city's winding medieval alleyways, it will be easier to believe that Perugia has a darker side. Its tens of thousands of students provide a lucrative market for drug peddlers – men such as Rudy Guede, the third defendant in the Kercher case.

Of late, their turf rivalries have become ever more violent. On the night after the summings up began, four Tunisians savagely beat a fifth in the historic centre. The night before, a 32-year-old man, also from Tunisia, was stabbed to death outside a bar.

Murder in this beautiful city is not such an unusual occurrence as might be imagined.