Dindo v. Whitney
United States Court of Appeals for the First Circuit
451 F.2d 1 (1st Cir. 1971)
After his insurer defended him without his own retained counsel in Whitney's (defendant's) 1966 suit over the same car accident, Dindo (plaintiff), unaware he could counterclaim, never did so, and that action settled; Dindo later retained his own attorney and brought this separate 1968 action against Whitney for his own injuries from the same accident, arguing the compulsory-counterclaim bar shouldn't apply because the prior suit ended in settlement rather than final judgment and because he hadn't known of his right to counterclaim.
Whether, where a party is entitled to bring a counterclaim based on the same transaction or occurrence as the opposing party's original claim, and where he fails to bring such counterclaim, he may be barred from bringing a later action with the same claims, even if the original suit was disposed of by settlement, rather than by final judgment.