21.   Investigators hope that a new survey with a special low-frequency sonar that can penetrate several inches of sand might locate some hidden wreckage.

22.   Investigators hope that the black boxes will tell them enough about the location of the problem that they can pick and choose what parts of the plane to retrieve.

23.   Investigators hope the flight data recorder will provide a clearer picture of what happened.

24.   Investigators hope the unopened Leahy letter contains DNA evidence or fingerprints from the killer.

25.   Investigators hope to resolve some of these questions when they examine the black boxes that hold recordings of the cockpit conversations during the final minutes of each flight.

26.   Investigators are hoping more witnesses will come forward.

27.   Investigators hope that a fingerprint lifted from one of the plastic bags will help them solve the case once a suspect is identified.

28.   Investigators hope that explaining the Pittsburgh crash might explain the earlier one, too.

29.   Investigators hope to decide within the next few days whether to file criminal charges.

30.   Maybe by floating his name investigators hoped to shake loose information from the stubborn, silent streets.