Triple Slaying Due For InvestigationRIO GRANDEāA grand jury is scheduled to be impanelled here Monday by Judge Lawrence Broeter to investigate, among other things, a shoet mg east of here last Sunday in which three men were killed.Five special deputy constables were charged with murder after the fight and have been moved from the Starr county jail to the Jim Hogg county jail at Hebbron-ville to await the jury's action.The men charged with murder in complaints by County Attorney H P. Guerra, Jr.. are Benigno Ram-lres. Amado Vera. Jr., Elias Solis. Martin Solis and Benito Saenz, all of La Grulla No trouble is brewing in Starr county about the five prisoners. Chief Deputy Sheriff Octavio Sanchez reported when the men were moved, but Rangers agreed the transfer was best, hesaid.Those killed in the shooting a week ago are Eulalio Elizondo, former deputy sheriff; Joae Cantu, former deputy constable; and Deputy Sheriff Ramon de la Cruz.