SAN FRANCISCO — Former BART cop Johannes Mehserle may face no further civil liability for the Jan. 1, 2009, shooting of Oscar Grant on a BART platform. But two other BART officers may have to stand trial for violating the rights of other detainees on that fateful night.

That was the impression left by questions at the U.S. Court of Appeals for the Ninth Circuit on Monday. If it sounds counterintuitive, it’s because of the nature of the claimants and the varying levels of misconduct each must prove in order to recover.