Watashi no Tadashii Onii-Chan / 真实的哥哥 / 私の正しいお兄ちゃん
Rank: 683rd, it has 4516 monthly / 12096 total views.
Authors: Morie satoshi
Genres: Japanese , Manga , Josei , Drama , Mystery , Psychological , Romance , Slice of Life
Release status: Ongoing
from cotton candy scans:

Rize, who’s a university student, met Kairi at her part-time job at the supermarket. While lending her shoulder to Kairi who has trouble sleeping, she is reminded of her older brother who left her when she was young, and Rize starts to feel affection towards him. However, she was shocked when she saw Kairi’s diary in his apartment saying that he had killed someone. What is the truth behind the person she likes? As the truth slowly comes to light, Rize starts chasing after her love for Kairi! This is Morie Satoshi’s roller coaster work that has crime, mystery and love!!