Shawn Nguyen bragged that he could sneak anything past airport security using his top-secret clearance as a federal air marshal. And for months, he smuggled cocaine and drug money onto flights across the country, boasting to an FBI informant that he was "the man with the golden badge."

Michael McGowan used his position as an air marshal to lure a young boy to his hotel room, where he showed him child porn, took pictures of him naked and sexually abused him.

Only a fraction of them have been charged with crimes, and some degree of misconduct occurs at all law enforcement agencies. But for air marshals, the stakes are uniquely high. Their beat is a confined cabin with hundreds of passengers in firing range. There are no calls for backup at 30,000 feet, putting a premium on sound judgment and swift action.

Over the years, the service has loosened some hiring practices:

• In 2002, the agency decided that recruits no longer had to pass a rigorous firearms test requiring them to prove speed and accuracy in close quarters similar to an airplane. The test is still used in training but is no longer a hiring qualification.

• In late 2005, the agency began hiring TSA screeners, new college grads and others with no law enforcement experience. The change departed from practice during the 9/11 ramp-up, when air marshals almost uniformly were chosen from law enforcement, such as the Border Patrol, federal Bureau of Prisons and police and sheriff's departments.

• Two years ago, officials suspended a requirement that air marshals pass a written psychological test and an interview with a psychologist or psychiatrist. Bray, the director, says the changes did not lower hiring standards and that it's unfair to suggest a TSA screener or a recent college grad could not be up to par after training.