Denpa Teki na Kanojo [LN ~ v01] (Electromagnetic Girlfriend)

Title: Denpa Teki na Kanojo / Electromagnetic Girlfriend

Author: Katayama Kentarou

Illustrator: Yamamoto Yamato

Genres: Action, Drama, Mystery, Psychological

Translation: 12it Translations

Juuzawa Juu is a delinquent high school boy who just wants to be left alone. One day, he is approached by Ochibana Ame, who claims that she knew him in a previous life, and now wants to serve him as his "knight". At first Juu wants nothing to do with Ame, but after a classmate is murdered, he accepts her help as he looks for the killer.

The insert images were placed by me (translator didn't) based on the raws so they are probably like 95% correctly placed.

If you perhaps never heard of this story or never watched its anime OVAs, it's a two-decades-old series.