The case against a former U.S. Naval Academy football player accused of sexually assaulting two women has been cast into doubt after new test results failed to find evidence the alleged victims were given a date-rape drug, his attorney said.

Military prosecutors requested a second hair analysis, and the results contradicted previous evidence in the academy's case against Kenny Ray Morrison, 24, of Kingwood, Texas.

Samples from the two women who said they were assaulted on separate occasions this year tested negative for gamma-hydroxybutyrate, or GHB, a common date-rape drug.

The tests were done by ChemTox, a French lab that is a leading testing center for GHB hair samples.

"In light of these new developments, I would think that they should drop the charges, at least those that relate to the alleged date-rape drug," said William Ferris, Morrison's attorney. "I can't imagine they can go forward on it."

The academy said in a written statement that "newly acquired additional information" had been forwarded to the investigating officer. The academy said his recommendation on whether to pursue a court-martial "is based upon a thorough and complete review of all available facts."

Another evidentiary hearing has been scheduled for Dec. 20.

Morrison was charged with two counts of rape, distribution of a controlled substance and assault, as well as several less serious offenses.

If convicted, he could be sentenced to life in prison. He was not allowed to graduate in May and has been assigned to the Washington Navy Yard while he awaits the outcome of his case.

Neither woman could remember many details of the alleged assaults when they testified.

In another case, a jury acquitted the academy's former quarterback, Lamar Owens Jr., of allegedly raping a female midshipman in her room in January, but convicted him of conduct unbecoming an officer and violating a direct order.

The jury referred the matter to the academy.

Owens was to have graduated in May. He is on assignment in Washington, pending a decision by the academy on whether he should be dismissed from the Navy or graduated and commissioned.