Two years after the events in Tantei Gakuen Q.

Kindaichi Hajime returns from his biking trip around Japan to meet Inspector Kenmochi and childhood friend Nanase Miyuki at the themed inn "Ruins." What awaits them is a vampire legend that comes to life in the form of a brutal serial murder...

Detective School Q is the story of a group of young students from Class Q of Dan Detective School (DDS), a prestigious and renowned detective academy founded by Morihiko Dan, the most famous detective in Japan, and the adventures and mysteries they unfold and solve together. They eventually work against Pluto, a mysterious organization which creates almost fool-proof plans that only a handful of detectives can solve.
The story was written under the penname Amagi, Seimaru.
(Source: Wikipedia)

From Tokyopop:
Kurumi Ayaki is a recently-retired police officer with a record of excellence on the force and the guts and guile to back it up. In order to earn some extra money for her upcoming wedding, she has to return to the force... and is "rewarded" with an assignment to an elite unit who solves crimes that have been classified as unsolvable.
Partnered with a mysterious young genius who is unable to feel emotions, or even to leave his room, she acts as his eyes and ears to piece together clues even as her own personal life falls apart around her.

The return of the famous teen detective, Kindaichi Hajime. With his keen intellect and sharp wits, there is no case he cannot solve, in the name of his grandfather!

The son of a genius magician, Yoichi Takato has been something of a polymath ever since his high school days.
However, his high school days are marked by boredom and an inability to open his heart to others.
When he happens to join the magic club, he meets with friends whom he can finally open his heart to.
But then, the curtain rises on a terrifying murder show!
A spinoff story with Hajime Kindaichi’s nemesis from “Kindaichi Case Files”, “the hellish puppet master” Yoichi Takato must solve this murder case, even though he is still in high school!!

"People often die around me."

A series of bizarre "deaths" stalk Genji, while a string of haunting memories and mystery surround him, all rooted in his childhood. A dear friend, a murder, and a curse. As more and more "deaths" unravel, the horrifying truth behind the origin grows ever more entangled. Seemingly the only keys to solve these mysteries, are the charismatic shinigami Touya, and Genji's own memories. Kindaichi Case Files writer Seimaru Amagi and Zetsuai creator Minami Ozaki come together to bring you a gripping mystery surrounding the past, memories, and the chain of deaths.

Lazy, unmotivated and sometimes pervertic kindaichi is a high school student with an IQ of 180! His grandfather was one of the best and most famous detectives in his time and kindaichi carries with him the responsibility of living up to his grandfather's name. In this series he takes on several mystery/ murder cases, accompanied by his best friend/ childhood friend miyuki.

Keep your eyes open for subtle clues and hidden meanings and try to solve them before kindaichi does! One of the most iconic mystery manga the rest of us grew up with.

Hajime Kindaichi returns from his biking trip around Japan to meet Inspector Kenmochi and childhood friend Miyuki Nanase at the Abandoned Boardinghouse "Ruins." What awaits them is a vampire legend and a brutal serial murder...

From Manga Box:

College student Sara Washizuki was shown a mysterious film photograph by paranormal photographer Tousei Ryuuzaki. In it was captured something she had left sealed away with her memories of a particular incident in her elementary school days… Based on the hit video game "Fatal Frame."