How prevalent is the internet in contemporary fiction?

It's a question best answered by a Booker Prize judge. In the modest opinion of this reviewer, however, the answer is: not very. Since its birth the novel has been a baggy monster with all-encompassing potential, but it has yet to find a way of incorporating the internet into its papery fabric. There are some profound and complex reasons for that, but for now there is TR Richmond's intriguing new thriller What She Left.

The mystery at the heart of this novel is the death of Alice Salmon, a 27-year-old journalist found drowned in a river in Southampton. Jeremy Cooke, an anthropology professor, decides to piece together Alice's life from the digital trace she has left behind. The resulting book is composed of carefully selected and ordered extracts from Cooke's research. There are blog entries, tweets, texts, emails, newspaper articles, diaries, and transcripts from chat rooms and police investigations. Even such seemingly trivial details as "Alice Salmon's 'Summer 2011' Spotify playlist" are included.

Out of this montage of communications emerges a cast of characters and suspects, but also the personality of Alice, a talented writer with a penchant for partying who likes to court the idea she is a "doomed heroine". Two of her "favourite quotations" on her Facebook page provide some insight to her character: "'Youth is a dream, a form of chemical madness'" (F Scott Fitzgerald); and "'Be the heroine of your life, not the victim'" (Nora Ephron). But a Facebook profile is a precarious way of learning about the inner life of a person and so it's fortunate that Alice is also a prolific diarist.

As an academic specialising in ethnolinguistics, Cooke is in an ideal position from which "to research, to record, to collect" Alice's life. However, he also has a fraught emotional history with the dead woman and her family, and he knows what he will unearth will make his own morally-suspect private life public. This might seem implausible: why would he want to defame himself? Cooke, however, has cancer and wants to die knowing the truth has been told.

Much of Cooke's story is conveyed through handwritten letters to a boyhood pen pal. As Cooke is a digital immigrant this correspondence is entirely plausible and these long epistolary sections are deftly handled. It is during these communications, and in the emails exchanged between Cooke and Alice's mother, that Richmond subtly shows us how innocent online behaviour can turn sinister in an instant, and that the internet can bring out the stalker and voyeur in all of us. This is what this novel does best: allow us to see cyberspace in a new light and present us with ethical complications in relation to our sleek, shiny digital paradise. For instance, in a world where privacy is being eroded and a public life is mandatory, who owns a life after it's finished?

As for the mystery of Alice's death, Richmond presents enough believable suspects and motives to keep the reader gripped, but the truth about how she dies is sadly a disappointment. In a metafictional afterthought Cooke writes: "no doubt readers drawn to its novelistic qualities will also castigate me for partly giving away the finale at the beginning (our heroine dies in Chapter One)". The real narrative mistake, however, is that the reader has no chance of working out the truth for themselves because the crucial information needed to do so is kept secret until the end. But for those of us who aren't simply concerned with whodunit, this can be easily overlooked in favour of other, more important, novelistic qualities.

As a digital immigrant detailing the life of a digital native, Cooke is aware he is trapped between two competing technologies - the codex and its digital successor - and the different conceptions of psychology they reflect. He worries that the idea of a cohesive self developing over time might be thrown into confusion by new technology: "how do people develop that sense of self nowadays, when all they write on is keyboards?"

As if to consolidate this quandary readers can explore Alice Salmon's world online, which - bizarrely - adds an extra layer of verisimilitude to the story. Alice even has a Facebook account, so after you've turned the final page you can keep on reading. You can even befriend her if you like. Why not? After all, you might have some things in common. You might also be a fictional construct, for instance.