51.   The scientists find clues in patches of rust, evidence of the interaction of iron and microbes, our ancient ancestors.

52.   The searchers found some clues to the source of jadeite, as the precious rock is known, for the Olmecs and Mayas.

53.   The searchers found some clues of where the Olmecs and Mayas might have obtained their jadeite, as the precious rock is known.

54.   They have found some clues in wild chimpanzee colonies, but their study is pushing deeper into the wild.

55.   University of Texas researchers may have found a clue to solving the mystery of declining sperm counts.

56.   Unless new clues are found, some veteran federal aviation experts said on Wednesday that it was increasingly possible that the crash might never be solved.

57.   Police resumed their search of abandoned buildings Friday, hoping to find clues to the whereabouts of missing federal intern Chandra Levy.

58.   A months-long Russian investigation failed to find clues to the killing.

59.   A U.S. Embassy official, speaking on condition of anonymity, said rescue teams have found no clues to the whereabouts of the father and son.

60.   Also Thursday, the Swedish Navy started trying to salvage the front cargo door of the Estonia in hopes of finding more clues about the cause of the disaster.