Once an indictment is returned, it is within the District Court's jurisdiction to set a bond. I understand that. But does that mean that when a defendant is arrested on a warrant issued based on an indictment that a JP can't read him his rights at the jail? And, if that is the case, where is it in the Code?

Thanks a bunch.

The answer is no. The magistrate who (generally) works at or near the jail admonishing jailed defendants may still read a defendant his rights after indictment. See Article 15.17 CCP.