1.   The mystery was deepened by her silence.

2.   And then her mother deepened the mystery.

3.   At the same time, it deepens the mystery of his peculiar genius.

4.   A Pentagon study, obtained by NEWSWEEK, only deepens the mystery.

5.   But all this has only served to deepen the mystery.

6.   But the passing days have only deepened the mystery about who the men are.

7.   Deepening the mystery is the fact that the day before their deaths last weekend, there were no outward signs of strain between the two, some friends said.

8.   Deepening the mystery, he said, is the fact that other die-offs have been observed several times this decade.

9.   Even when one of the girls is found, it only deepens the mystery surrounding her still-lost classmates and teacher.

10.   In one sense, the results only deepen the mystery of the dark matter.