Youth Faces Life For Slaying PairRIVERSIDE, Calif., Aug. 6 AP A young Negro air force sergeant, Lawrence Walker, 20, may spend the rest of his life in prison for the slaying of a young mother and father on a lonely road.A jury of 11 women and one man returned a verdict of first degree murder yesterday after 21 hours of actual deliberation. The jurors, who got the case last Friday, recommended that Walker be sent to prison for life. He will be sentenced August 15.Walker was convicted of shooting down Richard Cook, 18, on a desolate back road March 26; of kidnaping Doris Cook, also 18; of assaulting her with intent to rape her, and finally, of murdering her, too, as she fought off his advances in an old rock quarry 11 miles from the scene of the first murder.Young Cooks body was found sprawled beside the road. Near him lay his infant son, playing happily and unharmed on a pink blanket. Searchers discovered Mrs. Cook s body two days later, shot in the back.Walker s defense was underwritten by the National Association for the Advancement of Colored People. His lawyers, Crispus Wright and Leo Branton, wept openly on the courthouse steps after the verdicts were announced. They plan to appeal, they said, and, failing this, will seek a new trial.