[sufue]

Several titles by Leonard Gribble are on US Kindle Countdown.

At $0.99 for about 1/2 more day before going up to $1.99 for an unknown amount of time:

The Frightened Chameleon is in the Anthony Slade series.
link: http://www.amazon.com/Frightened-Cha...dp/B013RIQEXI/

Spoiler:

Superintendent Anthony Slade, of Scotland Yard, arrives in Paris to enquire into the strange disappearance of a man using a false name. He says to solve one of the most baffling cases of his career.

In company with Inspector Henri Duval of the Paris Sûreté, he journeys across Europe on the trail of a man it is not humanly possible to find. In a Swiss sanatorium he meets a person whose very existence is a secret kept from the world, and back in Paris with Duval he learns why Charles Gentian, the financial freebooter known as the Chameleon, was frightened.

This novel featuring the author's popular detective adds another triumph of detection to Slade's already notable record.

The Yellow Bungalow Mystery is in the Anthony Slade series.
link: http://www.amazon.com/Yellow-Bungalo...dp/B013RIQ3DE/

Spoiler:

Rosa Lee, adventuress and woman of mystery, is stabbed to death at her home, the Yellow Bungalow, while Martin Dare, the African explorer, is spending a few days with friends close by. She was murdered with an Arab dagger Dare had presented to his host. When Detective-Inspector Anthony Slade, Mr Gribble’s well-known detective, arrives on the scene he finds that four people might have committed the crime. Their alibis depended upon one another, their motives were strong, and two of them had visited the murdered woman secretly within a few minutes of the actual killing. Which of them was the murderer? Or was there some one unknown? Slade’s investigation soon revealed others who might have committed the crime, but somehow he was not satisfied with the theories he tried out. Actually he had made a brilliant piece of deduction and it was this that led him astray. But he solves the riddle in the end, and in his usual dramatic fashion.

At $1.99 for about one more day before going up to $2.99 for an unknown amount of time:

Murder First Class is in the Anthony Slade series.
link: http://www.amazon.com/Muder-First-Cl...dp/B00HRC5P8Q/

Spoiler:

A vintage English murder mystery set onboard a moving train.

The Riddle of the Blue Moon is a non-series title.
link: http://www.amazon.com/Riddle-Blue-Mo...dp/B00L7TSJV0/

Spoiler:

A muffled cry in the fog and a strangely-marked handkerchief flung from a speeding car set the Selby twins and their friend Chips Carpenter on a trail of dangerous adventure. The trail leads to a derelict roadhouse - The Blue Moon - and there they make a discovery which sends them all racing across the lonely, eerie Romney Marsh.