Generally it has been held that the doctrine of res ipsa loquitur is not applicable against multiple defendants where it is not shown that their liability was joint or that they were in joint or exclusive control of the injury-producing factor, or where the specific wrongdoer, among several possible, was not identified. A fundamental principle of res ipsa loquitur is that it is available to a plaintiff only when it operates substantially to identify the probable wrongdoer in a given situation. Conversely, the doctrine has been held applicable against multiple defendants where they are properly charged as joint tortfeasors on the theory that the defendants were engaged in a joint enterprise or were in joint control of the instrumentality causing damage to the plaintiff.
William B. Nagy, Res Ipsa Loquitur in Joint Tortfeasor Cases, 16 Clev.-Marshall L. Rev. 550 (1967)