Over the years advances in forensic science such as fingerprint, ballistics, and especially DNA testing have allowed for many cases to be solved just by re-examining the old evidence.

CNN: Solving the cold case: Time, DNA and ingenuity can help

This lawmaker and other sources said the administration favored federal standards, training and testing for security positions, and a larger federal presence at security checkpoints, especially at major airports.

CNN: Bush to propose aviation security measures Thursday