If you liked young detective games by Brendan Patrick Hennessy and Felicity Drake, you should probably also try Sixth Grade Detective. It's in the same genre, but with younger characters: the children are around 11 years old, and reading about their fluffy crushes is as sweet as watching Chico and Roberta dance. The mysteries you investigate are accordingly tamer - like finding a missing book in the second episode.
The characters are likeable and have some curious hidden depths; I was particularly surprised by Kyle, the leader of the bullies. And the fifth "case" was really heart-warming.