"The young men and women enrolled at the service academies must be able to learn and develop as future leaders in an environment free from sexual assault and sexual harassment," Panetta wrote. "They must feel secure enough to report without fear of retribution, and offenders must be held appropriately accountable."

Critics say the efforts of civilian leaders and military commanders, however well-intentioned, have failed to curb sexual assaults in the military.

Lawmakers have proposed taking prosecutions out of the chain of command. Under the current system, the power to bring charges, order a court-martial and affirm or overturn a verdict may rest with a single commander.

That system has come in for heightened criticism after an Air Force general tossed out the conviction of a fighter pilot under his command who was found guilty at court-martial of sexually assaulting a civilian contractor. The general then returned the officer to service.

Burke said the latest Naval Academy case shows a need for reform.

"We continue to ask: Why should justice in military sexual assault cases be placed in the untrained and biased hands of commanders whose own career interests may be served by covering up incidents like this one?" she said.

Warren, the Pentagon spokesman, said the Department of Defense has "no higher priority than the safety and welfare of our men and women in uniform, and that includes ensuring they are free from the threat of sexual harassment and sexual assault."

"Leaders at every level in this institution will be held accountable for preventing and responding to sexual assault in their ranks and under their commands," he said.

Baltimore Sun reporters John Fritze and Kevin Rector contributed to this article.