SAN ANTONIO -- Military officials say the initial flirtations that Staff Sgt. Luis Walker directed at the women he trained at a Texas Air Force base grew into something more sinister: threats and intimidation that eventually led to rape.

Walker's court-martial, resulting from a widening sex scandal at Lackland Air Force Base in San Antonio, began Monday with discussion of procedural issues in his case.

Opening statements had been expected by afternoon but debate among attorneys over various legal issues forced the military judge, Col. Wesley Moore, to delay them until Tuesday. Walker's father and two other family members were in the courtroom at the base.

Walker is among 12 instructors at Lackland who are being investigated in a scandal that has rocked one of the nation's busiest military training centers.

"We haven't had a case of this magnitude, certainly in recent memory," said Brent Boller, a spokesman for Joint Base San Antonio, which operates Lackland.

Walker faces the most serious charges in the case – 28 counts, including rape, aggravated sexual contact and multiple counts of aggravated sexual assault. He could get up to life in prison and a dishonorable discharge if convicted.

One of the legal issues debated Monday was whether to allow prosecutors to use in their opening statements a photograph Walker texted to one of his alleged victims. Walker appeared shirtless in the photo. Objections by defense attorneys over the photo's authenticity forced prosecutors to have the alleged victim briefly testify that the image had been sent to her by Walker.

"He sent a lot of photos," said the woman, whom The Associated Press is not naming because she is an alleged victim in the sex scandal. Prosecutors say Walker also told the woman that she was "hot" and "should have been naked."

Moore decided to allow prosecutors to use the photo of Walker.

The 10 female recruits Walker is accused of either sexually assaulting or engaging in inappropriate sexual conduct with are expected to testify during the court-martial. At least 31 female trainees have been identified as victims in the sex scandal.

Officials at Lackland are calling Walker's court-martial the "cornerstone case" in the ongoing investigation. A seven-member jury made up of military personnel will decide his case.

Walker's civilian attorney, Joseph Esparza, declined comment Monday.

A two-star general, Maj. Gen. Margaret H. Woodward, has launched a separate, independent investigation.

Advocates for female service members and members of Congress have started taking notice.

"It's a pretty big scandal the Air Force is having to deal with at this point," Greg Jacob, a former Marine infantry officer and policy director of the Service Women's Action Network, said last month. "It's pretty substantial in its scope."

The sexual misconduct at the base apparently began in 2009, but the first woman didn't come forward until last year. The first allegations were levied against Walker, who is accused of crimes that allegedly took place between October 2010 and January 2011.

According to the Air Force charge sheet, Walker had sexual intercourse with four of the 10 female recruits. He also is accused of making flirtatious or sexually suggestive comments, sending inappropriate text messages and sometimes groping his recruits.

The charge sheet also includes allegations that Walker forced five recruits to engage in sexual acts by threatening their military careers. He's accused of intimidating two of the women into lying about his alleged misconduct.

Walker was a trainer for about 18 months, until he was removed from his position in June 2011. He joined the Air Force in 2004 and previously was stationed at Dover Air Force Base in Delaware and at facilities in Montana and Korea. The Air Force is withholding his age and hometown.

Lackland is where every American airman reports for basic training – about 35,000 a year. About one in five is female, pushed through eight weeks of basic training by a flight of instructors that are about 90 percent male.

Six of the 12 instructors under investigation for misconduct face charges ranging from rape to adultery. Officials say nine of those instructors were in the same squadron.

The first court-martial in the case resulted in a plea agreement in June, when Staff Sgt. Peter Vega-Maldonado admitted to having sex with a female trainee. He struck a plea deal for 90 days of confinement. He later acknowledged being involved with a total of 10 trainees, a number previously unknown to investigators.

___

Also on HuffPost:

Loading Slideshow...
  • Anthony Weiner's Online Romance

    Rep. Anthony Weiner (D-N.Y.) was forced to <a href="http://www.huffingtonpost.com/2011/06/16/anthony-weiner-resigns_n_878229.html" target="_hplink">resign</a> following a lengthy media investigation triggered after he accidentally sent his Twitter followers a picture of himself in his underwear. In the aftermath of the initial tweet, Weiner <a href="http://www.huffingtonpost.com/2011/05/31/anthony-weiner-twitter_n_869008.html" target="_hplink">claimed</a> that his account had been hacked, but subsequent developments showed that he had contacted a <a href="http://www.huffingtonpost.com/2011/06/16/anthony-weiner-photos-women_n_878211.html" target="_hplink">number of other women</a> online, at times engaging in <a href="http://www.huffingtonpost.com/2011/06/07/anthony-weiner-facebook-chats_n_872783.html" target="_hplink">raunchy conversation</a>.

  • Eliot Spitzer Client Number 9

    In March 2008, a federal investigation revealed that Gov. Eliot Spitzer (D-N.Y.) had habitually patronized a high-priced prostitution agency, spending up to $80,000 on the service.

  • Arnold Schwarzenegger's Mistress

    Revelations surfaced earlier this year that the former California governor and movie star had <a href="http://www.huffingtonpost.com/2011/05/18/arnold-schwarzeneggermild_n_863882.html" target="_hplink">fathered a child</a> with his maid during an affair that took place during the 1990s. The child is now in his teens. In a statement to the <a href="http://www.latimes.com/news/nationworld/nation/la-me-0517-arnold-20110517,0,312678.story" target="_hplink"><em>Los Angeles Times</em></a> in May, Schwarzenegger confessed to the relationship: <blockquote>"After leaving the governor's office I told my wife about this event, which occurred over a decade ago," Schwarzenegger said Monday night in a statement issued to <em>The Times</em> in response to questions. "I understand and deserve the feelings of anger and disappointment among my friends and family. There are no excuses and I take full responsibility for the hurt I have caused. I have apologized to Maria, my children and my family. I am truly sorry."</blockquote>

  • Mark Sanford's Secret Trip To Buenos Aires

    When Governor Mark Sanford (R- S.C.) went missing for a few days in June 2009 he said he was hiking the Appalachian Trail. He later confessed he was actually in Argentina visiting his "soul mate." He and his wife have since gotten divorced.

  • Eric Massa's Tickling

    Rep. Eric Massa (D-N.Y.) <a href="http://www.huffingtonpost.com/2010/03/05/eric-massa-resigning-new_n_487870.html" target="_hplink">resigned</a> in 2010 following <a href="http://www.huffingtonpost.com/2010/03/03/eric-massa-to-retire-new_n_484288.html" target="_hplink">mounting questions</a> about his conduct that culminated in a House ethics investigation of <a href="http://www.huffingtonpost.com/2010/03/04/eric-massa-house-ethics-p_n_486424.html" target="_hplink">harassment allegations</a> brought forth by a male aide. Shortly after stepping down, Massa <a href="http://www.huffingtonpost.com/2010/03/09/eric-massa-and-glenn-beck_n_492441.html" target="_hplink">appeared</a> on Glenn Beck's television show and described part of an incident that had triggered the charges. "Not only did I grope him, I tickled him until he couldn't breathe," he said. "I should have never allowed myself to be as familiar with my staff as I was... I own this misbehavior."

  • David Wu's Alleged Teen Encounter

    On July 26, Rep. David Wu (D-Ore.) <a href="http://www.huffingtonpost.com/2011/07/26/david-wu-resigns-sex-scandal_n_909734.html" target="_hplink">announced</a> that he would step down pending the conclusion of ongoing negotiations to raise the debt ceiling. Wu, who had fielded <a href="http://voices.washingtonpost.com/thefix/house/should-david-wu-resign.html" target="_hplink">prior criticism</a> for erratic behavior in the run up to his successful 2010 reelection -- he <a href="http://www.huffingtonpost.com/2011/02/23/oregon-newspapers-gop-david-wu-resign_n_827462.html" target="_hplink">emailed staffers</a> a picture showing him wearing a tiger costume -- is currently facing allegations that he engaged in an unwanted sexual encounter with an 18-year-old. Wu has claimed the action was consensual.

  • Chris Lee's Craigslist Follies

    Rep. Chris Lee (R-N.Y.) took part in perhaps the shortest Washington scandal of all time earlier this year, when a <a href="http://gawker.com/#!5755071/married-gop-congressman-sent-sexy-pictures-to-craigslist-babe" target="_hplink">report</a> that he had sent shirtless pictures to a woman he contacted on Craigslist prompted his <a href="http://www.huffingtonpost.com/2011/02/09/chris-lee-resigns-after-c_n_821080.html" target="_hplink">resignation</a> mere hours later.

  • John Ensign Has Affair With Aide's Wife

    In June 2009, Sen. John Ensign (R-Nev.) admitted to having an affair with the wife of a close friend and top aide. In April of this year, he <a href="http://www.huffingtonpost.com/2011/04/21/john-ensign-resigns-reports_n_852285.html" target="_hplink">announced</a> that he was resigning amid a high-profile ethics probe.

  • Jack Ryan Taking Jeri Ryan To Sex Clubs

    According to custody records, 2004 Illinois Republican Senate hopeful Jack Ryan brought his wife -- actress Jeri Ryan -- to sex clubs in various cities with the intent of having sex in public. Ryan was forced to drop out of the race amid the scandal that flared afterward.

  • John Edwards And Rielle Hunter

    In August 2008, Sen. John Edwards (D-N.C.) finally confessed that he'd had an affair with a former campaign worker after being exposed by the <i>National Enquirer</i>. He met Rielle Hunter, his future campaign videographer, in a bar. Edwards <a href="http://www.huffingtonpost.com/2010/01/21/john-edwards-admits-pater_n_431006.html" target="_hplink">admitted</a> fathering the child in early 2010.

  • Larry Craig Toe-Tapping In Airport Bathroom

    Sen. Larry Craig (R-Idaho) was arrested in June 2007 for lewd conduct following an unusual interaction with another man in a bathroom stall at Minneapolis-St. Paul International Airport. Craig did not resign immediately, but he did not run again.

  • Mark Foley Sends Sex Messages To Underage Pages

    In September 2006, then chairman of the House Caucus on Missing and Exploited Children Rep. Mark Foley (R-Fla.) was forced to resign amid a scandal involving sexual IM and email conversations with male pages. Foley has since admitted that he is gay.

  • David Vitter Caught With Prostitutes

    Sen. David Vitter (R-La.) was exposed as a former client of the "DC Madam" prostitution ring in 2007. She even called him during votes. The conservative senator was reportedly also a regular at a New Orleans brothel. Vitter ran for reelection and won in 2010.

  • Tim Mahoney Paid Off Mistress Staffer

    In October 2008, it was reported that Rep. Tim Mahoney (D-Fla.) had paid a former staffer-turned-mistress $121,000 to keep her from filing a lawsuit. Mahoney later admitted to having more extramarital affairs.

  • Vito Fosella Bailed Out From DUI By Mistress

    In May 2008, Rep. Vito Fossella (R-N.Y.) was arrested for drunk driving, taken to jail, and bailed out by his mistress. After conflicting stories and poorly constructed lies, he finally admitted that he had been engaged in an affair with the woman and was the father of her 3-year old child.

  • Don Sherwood Accused Of Choking Mistress

    In 2005, opponents of Rep. Don Sherwood (R-Pa.) released a D.C. police report from 2004 alleging that Sherwood had choked his mistress. The release of the report forced Sherwood to admit to a five-year affair with the woman.

  • Gary Condit And Murdered Intern Chandra Levy

    After congressional intern Chandra Levy went missing in May 2001, Rep. Gary Condit (D-Calif.) became the center of a scandal that led to his admitting an affair with Levy. In 2009, Levy's murderer was determined to be a man already in prison for other murders.