bark up the wrong tree

An allusion to a situation in which a hunting dog misidentifies the tree up when it has chased an animal and positions itself at the base of another tree, barking upward at the branches.

• "The investigator spent days trying to prove the butler committed the murder, but it turns out he was barking up the wrong tree."
• "You're not the first man who has made such a mistake, and found he was barking up the wrong tree."
• "They all went into the house, and left me feeling a precious idiot. I had been barking up the wrong tree this time."
• ""We want West. He's a cowardly murderer—killed the man who trusted him." . . . "Of course we may be barking up the wrong tree," the officer reflected aloud. "Maybe West isn't within five hundred miles of here.""
• "After three failed marriages I realised that I may have been barking up the wrong tree and should abandon the search for the perfect wife."