A Soviet defector has been charged with the murder of his live-in lover, a Russian woman who testified last year at the spy trial of former FBI Agent Richard W. Miller, Los Angeles County Deputy Dist. Atty. Lisa Hart said. Vladimir Ratchikhine, 44, is accused of killing Ludmilla Kondratjeva, 38, last December after the two had a domestic dispute. A car with Kondratjeva's body inside was found at the foot of a cliff near Santa Monica and an autopsy later showed she had drowned. Kondratjeva was a friend of Miller's Soviet lover and had testified for the prosecution during his trial. Ratchikhine is scheduled to be arraigned this morning in Santa Monica Municipal Court.