Hey guys, i am looking for a manga that i believe was another version of Blood Alone or something similar but it contained sex scenes.

if i remember correctly it started of with a murder in a park and the main character who is a detective (i think) sees a girl among the trees in the park, then when he goes to her apartment she gives him advice about the case, i remember there being sex scenes between him and the girl.

can someone help me with this one please