During investigations the wizard rolls an investigation check, the cleric rolls an investigation check and the barbarian does nothing because they dumped wisdom
You might be playing it wrong.
During investigations Wizard checks the books in the library, references his own notes, chats up local researcher community. Creates and sends Arcane Eye, spreads his familiars, tries Clairvoyance.
Cleric visits a local church, talks to the priests and churchgoers, prays to the Divine, maybe convinces the town to join her in the crusade against the target and lits the town on fire, while villages attack the nobleman mansion looking for the culprit and plunder.
Barbarian goes to the local tavern to drink with the local guards. Helps local elder find his kitten. Maybe talks to a local hunter and they bond over a bear hunt they just finished, maybe about the beauty of wilderness… One thing leads to another, a secret touch, a hidden look, a moment of courage, a stolen kiss… What I was talking about?