Crime-scene investigations play an important role in gathering evidence for criminal trials -- from fingerprints and blood samples to DNA and digital data. But expert witnesses known collectively as forensic scientists or criminalists must analyze the evidence to help the judge and jury determine a defendant's guilt or innocence. A congressionally mandated study, however, says major changes are needed to strengthen forensic science. The reliability of some identification techniques used in court is unproven, the report says, and even established techniques such as fingerprint analysis are less certain than commonly believed. In addition, crime laboratories are underregulated, underfunded and understaffed -- and may have a conflict of interest because they are tied to law enforcement agencies. Criminal-defense lawyers are applauding the report, as are some forensics experts. But resistance from law enforcement agencies and crime labs themselves may slow or block reforms.

Kenneth Jost is Supreme Court editor, CQ Press; associate editor, CQ Researcher; and author of The Supreme Court Yearbook since the 1992-1993 edition.