The prosecution and defense in a Frisco murder case told a 5th Judicial District Judge on Sept. 9 they have been negotiating a potential plea deal and will know by the next hearing whether or not the parties will have an agreement. At a status conference hearing, public defender Carolin Lopez told Judge Reed Owens that the parties were still waiting on results of DNA testing in the case concerning Luis Mendez-Hernandez, 19. Owens in May found pr…