4 Free eBooks to Read in October 2025 for Mystery, Thriller, and Crime Fans

Solve crimes with these mystery ebooks—free, this month only.

postimage
camera-iconPhoto Credit: Martin Vorel

Those of us who are voracious readers can never get our fill. There is always some intriguing new mystery or riveting new thriller to devour, and an endless stream of new releases to add to our reading wish lists.

But sometimes you just crave a classic. These are the books that created the scaffolding for the genres we know and love—and they are just darn good.

Every month, we’re bringing you a selection of free ebooks to read that are perfect for all you timeless sleuths out there—lovers of all things mysterious and thrilling.

The Black Gang

The Black Gang

By H. C. McNeile

The First World War is over, but Captain Hugh ‘Bulldog’ Drummond finds new hostilities at home. After discovering that bribery and blackmail are corrupting England’s democratic system, the former soldier creates the Black Gang, an extra-legal team of veterans.

Their objective is to track down and neutralize the conspirators. They execute a plan to lure the criminal mastermind responsible for these subversive plots to England.

When the villains finally gather at a private country house, the Black Gang attacks, using force to quickly subdue the criminals who had been operating just outside the law.

With his trap successfully set, Drummond’s entire operation is unexpectedly jeopardized by a seemingly innocent meeting– an invitation to tea at the Ritz with a charming American clergyman and his daughter.

This apparently harmless meeting risks exposing the Black Gang's identity, placing Drummond directly in danger from the powerful criminal network he intended to dismantle. 

The After House

The After House

By Mary Roberts Rinehart

The luxury yacht was meant to be a peaceful escape, but it becomes a floating death trap when a series of brutal, inexplicable murders turns the voyage into a high-seas house of horrors.

As fear and suspicion grow among the privileged passengers and volatile crew, the vessel sails into a terrifying web of psychological tension and intrigue.

Caught in the middle of the growing panic is Ralph Leslie, the ship's steward, who must secretly piece together the clues and motives.

This classic of early 20th-century detective fiction keeps the reader completely off-balance, showcasing Rinehart's skill for tightly plotted mysteries with unexpected twists.

The Wicked Marquis

The Wicked Marquis

By E. Phillips Oppenheim

The Marquis of Mandeleys lives like a king, owning every acre he surveys– except the tiny patch held by tenant Richard Vont, a man consumed by an eighteen-year-old score.

After the Marquis involved himself in the life of Vont’s daughter, the bitter father engineers a meticulous, destructive plot for revenge.

This novel is not just an old thriller; it’s a compelling portrait of class resentment and obsession, setting up a seemingly clear conflict between a powerful aristocrat and the ordinary man he wronged.

As the conspiracy unfolds, Vont's righteous anger comes into question, dramatically reversing the roles of hero and villain. The reader is pulled into a high-stakes investigation to determine if the supposed victim is truly innocent, and if the mercenary will complete his deadly assignment.

This psychological thriller remains captivating thanks to its unpredictable plot and its sharp look at how appearances can fatally deceive.

The Hollow Needle

The Hollow Needle

By Maurice Leblanc

The gentleman-burglar Arsène Lupin is on the trail of his greatest prize yet: the legendary Hollow Needle, a secret vault containing the cumulative treasure and priceless historical secrets of the Kings of France since the time of Julius Caesar.

This quest for unfathomable wealth and power draws in two of Lupin's old rivals, the seasoned Detective Ganimard and the brilliant, thinly disguised English sleuth, Holmlock Shears. 

This time, a new threat emerges: Isidore Beautrelet, a genius high school student and amateur detective.

As Beautrelet closes in on the riddle of the Needle– discovering decoy locations and exposing Lupin's hidden identity– this becomes an intense, high-stakes game of cat-and-mouse between the master thief and the teenage prodigy.

Readers will be captivated by this clever, twist-filled battle of wits, proving that the blueprint for today's most engaging cat-and-mouse thrillers was perfected over a century ago.