2 Nen a Gumi Tantei Kyoku [7] (Kadokawa Tsubasa Bunko)

[Machine Translation] There was a case of a street attack that attacked only elementary school students! The incidents escalate, with people being beaten with baseball bats and stabbed with knives. In order to catch the culprit, the elementary school students formed a detective team! At the same time, Mitsugi, who was asked to investigate a junior high school student's affair with his girlfriend, was unexpectedly caught by the police...! The 2A Detective Agency, as well as our own Eiji and Yasunaga, also cooperate in the investigation. The culprit is an unexpected person! 2A Detective Bureau, Vol. 7! From upper elementary school.

小学生だけを襲う通り魔事件が起きた!バットでなぐられたり、ナイフで刺されたり、事件はエスカレート。犯人を捕まえるため、小学生は探偵団を結成した!そのころ、中学生の彼女の浮気調査の依頼を引きうけた貢は、思いがけないことから警察に捕まって...!?2A探偵局と、ぼくらの英治や安永も捜査に協力。犯人は意外な人物!?2A探偵局、第7弾!!小学上級から。