After Officer Porter's trial ended, the state sought to compel Officer Porter to testify against Officer Goodson, the driver of the van that transported Freddie Gray, whose trial was scheduled to begin last week. When the circuit court granted the state's request, the defense appealed. The Maryland Court of Special Appeals postponed the trial while it considers the issue. In seeking the order to compel, the state suggested in court filings that Officer Porter's testimony is critical to the state's case. Why does the state want to rely on Officer Porter, someone it has repeatedly called a liar, to convict Officer Goodson?