Cosykiller — for the armchair sleuth

The case files 3 live · posted worldwide

Every case,
hand packed for quality.

Immerse yourself in mystery with each box. Each box has been designed for authenticity, with historic cross referencing and detail that will leave you wanting to find out more. Our limited edition print runs, create quality rather than quantity. Cases sell out fast.

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New to Cosykiller? Unsure what we do suits your style of sleuthing? Test your mettle with "Shadows in the Gallery" our self contained single box story. Work your way up to The Secret of Site Q – our 12 part investigation.

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Showing 8 of 8 cases

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Shadows in the Gallery — the full post-war case file spread across a desk, photographs, military papers and a coded note

Case № SHADO-012-4 hours

Europe 1946

Shadows in the Gallery

A body discovered in a bricked up cellar unlocks the start of a cold case investigation.

£45Open the case
The Site Q case file laid out on a dark wooden table — National Geographic article, army-green hurricane lamp, Mayan glyphs and expedition correspondence

Case № SITEQ-019-12 hours

Mexico and America 1950s-1980s

The Secret of Site Q

A body uncovered at an abandoned campsite in the dense Mexican rainforest reveals there was more to a simple tragedy.

£285Open the case
Letters, a Post Office telegram, a Simla theatre programme and a hand-coloured map laid out across the case table — the Inheritance case file

Case № INHER-016-11 hours

Simla, India 1934

An Inheritance of Murder

An heir hunter team reaches out to you to ascertain if you are the long lost heir of an English Estate.

£285Open the case
Marlborough House seen through a rain-streaked window at dusk, a silhouetted hand pressed to the glassSold out

Case № MARL-0110 hours

Whitechapel, London, autumn 1888

Murder at Marlborough House

Victorian Whitechapel, 1888. Not the one you're thinking of — but the same streets, the same fog, the same kind of quiet cruelty.

No longer available
A vintage Post Office telegram reading "The Hidden Listener" with the Cosykiller stamp affixedSold out

Case № HIDDEN-019 hours

Interwar Britain, 1930s

The Hidden Listener

An interwar radio operator. A coded knitting pattern. And somebody in the room who shouldn't have been listening.

No longer available
The Legend of Ching Shih — South China Seas pirate-era mystery placeholderSold out

Case № CHING-019 hours

South China Seas, 1810

The Legend of Ching Shih

South China Seas, 1810. The most successful pirate in history vanished with a fortune. Somebody wrote it all down, and the paper survived.

No longer available
A granite pharaoh statue lit from below against a dim museum wall — the opening of The Curse of Humanrah case fileSold out

Case № HUMAN-0111 hours

Valley of the Kings, Egypt

The Curse of Humanrah

With a series of mysterious deaths following the opening of the previously unexplored tomb of Humanrah, it falls to you to crack the case.

No longer available
The Virginia Steele case file laid out on a desk — a leather-bound notebook, period photographs and the orphanage paperworkSold out

Case № ORIG-VS6 hours

Simla, India, 1911-1912

Cosykiller Origins: Virginia Steele

Simla, 1911. The Raj's summer retreat — and an orphanage fire nobody wanted investigated. A three-box mini series.

No longer available

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