TOWARDS the end of Juan Gabriel Vásquez’s new novel, the author, speaking directly to the reader, explains that at one point in his life he was forced to re-evaluate everything he knew about his native Colombia. This was a country which “began to turn into a place of shadows out of which jumped horrible creatures as soon as we dropped our guard.”

All of Vásquez’s novels have set out to shine a light on those shadows and expose those creatures. His debut, The Informers, charted the desperate plight and misplaced faith of a Jewish family which fled Nazi Germany for sanctuary in Colombia; The Secret History of Costaguana reworked the origins of Joseph Conrad’s Nostromo while chronicling Colombia’s turbulent past; and The Sound of Things Falling studied the legacy of the brutal war between drug cartels and government.

In The Shape of the Ruins – elegantly translated by Anne McLean – Vásquez continues to scrutinise his nation’s convulsive history, this time exploring how a solitary act unleashed carnage, chaos and “a collective neurosis that has taught us to distrust each other for more than half a century.”

The book’s narrator-protagonist is Vásquez himself. When attending a party thrown by his friend Dr Benavides he is introduced to Carlos Carballo, a man obsessed with the 1948 murder of future JFK-style president Jorge Eliécer Gaitán. Carballo has always smelled a rat, believing in cover-ups, fall guys and second shooters. After arguing his alternative version of events he asks Vásquez to open his mind and write a book about who was really behind the killing.

Vásquez dismisses Carballo as a fantasist. But years later, after encountering him again at a funeral, he is talked into re-examining the details of another, earlier political assassination. Soon Vásquez finds himself questioning old truths and weighing up new theories, and in doing so he gains a greater understanding of Carballo’s ruthless motivation and Colombia’s inescapable violence.

At over 500 pages, this is Vásquez’s biggest book – but not his best. Large swathes of it are delivered in long speeches. Information is unloaded rather than unearthed. What should be storytelling is, on occasion, just telling.

However, there is still a lot to admire. Like Don DeLillo’s JFK-themed Libra, the novel is an intoxicating blend of fact and fiction. The narrative flits between present and past and is intercut with authenticating photos, testimonies and newspaper articles. When not satisfying his “morbid curiosity” by dredging “the cesspool of Colombian history” or sifting conspiracy theories, Vásquez captivates us with other glimpses of himself: as a distracted family man, a dedicated author, or a bogotano chasing the ghosts of the dead in “the cemetery city.”

In his previous novel, the shorter, tighter Reputations, Vásquez posed the question: “What good is ruining a man’s life, even if the man deserves ruin?” This latest, more ambitious novel deals with ruins on a grander scale – those a country was reduced to after decades of bloodshed. Less would have been more, but Vásquez hits far more than he misses, and packs a considerable punch.