Commonwealth v. (And

Codefendants Luis Taveras and Daileen Cruz were each convicted of distribution of heroin and an accompanying school zone violation. On appeal Taveras argues, among other things, that the evidence was insufficient to show that he engaged in a joint venture to distribute heroin. Cruz raises three arguments: her confrontation rights were violated when the judge allowed a substitute chemist to testify as to the identity of the substance that was tested; the judge erred by allowing a State trooper to testify as both a percipient witness and an expert witness; and the evidence was insufficient to…