The night began like many at Boorda Hall, a five-story barracks at Naval Station Great Lakes, the Navy’s premier training base on the shore of Lake Michigan in Illinois.

Somebody announced a party, and the hard drinking and beer pong began. A 21-year-old Marine lance corporal, so drunk on rum and Mountain Dew she was slurring her words, went to look for Kyle Antonacci, a Navy seaman she’d been dating off and on. Antonacci soon texted his friend Mike Pineda to help him deal with her.

Both men had sex with her that night. But what distinguished May 8, 2009, from dozens of other party nights in the barracks — what turned it into a mystery that investigators still are trying to unravel — was what happened afterward.

Pineda, a seaman from Barstow, Calif., training as a Navy SEAL, spent three months in jail for sexual assault. Antonacci, a 22-year-old ordnance disposal trainee from Long Island, N.Y., was threatened with prosecution. The case didn’t go far: Antonacci’s body was found hanging in a closet, his nose bleeding, his face and back bruised.

The armed forces face a skyrocketing number of sexual assault cases. This investigation in particular — involving dozens of witnesses, lie detector tests and forensic exams — points up the difficulty of pursuing such prosecutions in the barracks, where drinking and sex often go hand in hand.

Witnesses, their memories clouded by alcohol, told stories that omitted key details. Antonacci admitted lying. The Navy told Antonacci’s parents that he was a troubled young man who had taken his own life. But the parents never believed it, and neither did Pineda.

For years, the parents and Pineda, 31, have tried to prove that the Naval Criminal Investigative Service hid the truth to conceal its own bungled rape investigation. And they are not alone. The former Lake County coroner says he was denied access to key evidence and pressured to call the February 2010 death a suicide. He now believes Antonacci was murdered.

“They used him as a pawn in a game to win a case, and somebody needs to answer for that,” Pineda said.

Roughly one out of five military women say they were victims of unwanted sexual contact by another servicemember since joining the military, according to a Pentagon health survey conducted in 2011 and released Monday.

The highest rate of sexual abuse was in the Marine Corps: Nearly 30% of women said they suffered unwanted sexual contact by another military member. Close behind were the Army and Navy, each with about 24% of women raising the issue.

The sexual abuse rates appear to be significantly higher than similar survey findings from the 2008, although the Pentagon changed the way it conducted the 2011 survey of 34,000 troops, so comparisons are difficult.

Still, questions about unwanted sexual conduct were virtually identical in both surveys and in 2008, 11% to 12% of female soldiers and sailors said they were victims of unwanted touching, along with 17% of women who were Marines. About 29,000 troops were surveyed in 2008.

The survey results, combined with other recent research, "shows sexual assault is a persistent problem in the military," said Army Maj. Gen. Gary Patton, director of the Pentagon's sexual assault prevention office. "We realize we have more to do."

The results surface at a time when a growing number in Congress are concerned about sexual assault and harassment in the military, and the low rate of criminal complaints vs. a high rate of sexual assaults recorded in anonymous surveys such as the one released Monday.

"Obviously, this report is very alarming," says Sen. Kirsten Gillibrand, D-N.Y., chair of the personnel subcommittee of the Senate Armed Services Committee.

She is working on legislation that would remove from the chain-of-command the decision to file charges in a felony case, including rape or other sexual assault.

Gillibrand says that victims of sexual assault in the military hesitate to complain because they fear retribution or skepticism from commanders. "This (survey) report highlights the need for legislation," she says.

Military leaders oppose the changes she is seeking.

The investigation of accused military rapists should be removed from the chain of command and handed to trained prosecutors, perhaps installing an era of civilian oversight within the armed forces justice system, according to senators who Wednesday [March 13] heard testimony from three ex-service members who were sexually assaulted while on duty.

The push for an overhaul in how the military handles reported rapes in its ranks was repeatedly underscored during the hearing by references to the recent decision by a top Air Force general to overturn a military jury’s verdict against a fellow pilot convicted of raping a woman who had been assigned to a hospital at Aviano Air Base in Italy.

The Aviano ruling — which set aside a one-year brig sentence for the convicted rapist — is “yet another example of an abuse of authority taken by a commander that will have a chilling effect on military judges, prosecutors, and juries and inhibit victims from coming forward,” testified Brian Lewis, a former Navy petty officer, who was raped in 2000 by a senior non-commissioned officer service. Lewis became the first male rape survivor ever to testify before Congress about such an assault. The hearing also marked the first Senate attention to military sexual assault in nearly 10 years.

“The epidemic has not been successfully been addressed in decades of review and reform by the Department of Defense or by Congress … (There is) inherent bias and conflict of interest present in a broken military justice system,” Lewis testified. “The reporting, investigation, prosecution and adjudication of sexual assault must be taken out of the chain of command and (placed) into an independent office with professional, military and civilian oversight. (The current system) … is another way that the Department of Defense fails us.”

Another veteran, former Army Sgt. Rebekah Havrilla, told the panel — part of the U.S. Senate Committee on Armed Services — that she was raped in 2007, a week before she was scheduled to leave Afghanistan for the United States. When she confided the attack to an Army chaplain, he told her the rape “was God’s will and that God was trying to get my attention so that I would go back to church,” she testified, adding that her rapist later posted on the Internet images of her sexual assault.

Havrilla testified that she initially decided to not report the rape because she feared retaliation from the male members her her bomb-disposal unit. After she did report the rape to her commanders, the alleged offender was not punished, she further testified.

Sen. Jeanne Shaheen, D-N.H., shares her thoughts on the staggering number of military sexual assaults and what Congress can do to stop them.

“Commanders were never held accountable for choosing to do nothing. What we need is a military with a fair and impartial criminal justice system, one that is run by professional and legal experts, not unit commanders,” Havrilla testified.

At least four senators on the Senate subcommittee said they favored the notion of adding independent prosecutors to the portion of the military-justice system that deals with sex assaults - or agreed that some version of fundamental reform is needed in how the armed forces handle rape reports.