Case Closed, Vol. 2 by Gosho Aoyama

[Viz] Can Detective Conan crack the case…while trapped in a kid’s body? When ace high school detective Jimmy Kudo is fed a mysterious substance by a pair of nefarious men in black—poof! He is physically transformed into a first grader. Until Jimmy can find a cure for his miniature malady, he takes on the pseudonym Conan Edogawa and continues to solve all the cases that come his way. Conan must contend with the murder of a man who burns to death while the prime suspect has the perfect alibi; he helps a seemingly sweet and innocent girl look for her missing father; and he still has time to explore a haunted house with some of his new friends from elementary school! All the clues are there--can you piece them together and solve these baffling cases before Conan does?