WASHINGTON – Defense Secretary Leon Panetta unveiled what he called “a strong package’’ aimed at enhancing the power of Pentagon officials to investigate those in the military who sexually assault fellow service members.

At a news conference Monday night where he was joined by U.S. Rep. Mike Turner, R-Centerville, Panetta said the Pentagon will create in each branch of the service a special unit of investigators and prosecutors trained in investigating sexual assault cases.

In addition, Panetta said he would issue a directive that would require the unit commanders to report accusations of sexual assault to a special court martial, which he said would guarantee that the charge would be examined by a colonel in the Army or Air Force or a captain in the Navy.

“The most important thing we can do is prosecute the offenders; deal with those that have broken the law and have committed this crime,’’ Panetta said. “And if we can do that, then we can begin to deal with this issue — not only prosecute those that are involved — but more importantly send a signal that this is not something that we are going to ignore in the United States military.’’

The changes are designed to deal with the type of crime that led to the murder of Marine Lance Cpl. Maria Lauterbach, who grew up in Vandalia. Lauterbach was denied a base transfer after she accused fellow Marine Cesar Laurean of sexual assault.

Lauterbach, 20, disappeared in late 2007 and her remains were found in a shallow pit in Laurean’s back yard in North Carolina in January 2008. She was eight months pregnant when she was murdered. Laurean was convicted of first-degree murder and is serving a life sentence without parole.

The Lauterbach family could not be reached Monday night for comment.

Panetta and Gen. Martin Dempsey, chairman of the Joint Chiefs of Staff, briefed Turner and other members of Congress Monday about the changes in Pentagon policy. Most of those changes, including creation of the special victims’ unit, will need congressional approval.

Turner and Rep. Niki Tsongas, D-Mass., co-chair what is called the Military Sexual Assault Prevention Caucus of Congress. Turner said the changes Panetta outlined are included in the House version of the annual defense bill.

“Our men and women in uniform should not fear their fellow service members,’’ Turner said at the news conference. “Sexual assault is not an issue of bad behavior . . . It is a crime.’’

While insisting he was outlining a strong series of changes, Panetta acknowledged “there’s no silver bullet when it comes to this issue. But what is required is that everyone from the secretary to the chairman of the joint chiefs all the way down at every command level, be sensitive to this issue, be aware that they bear the responsibility to take action on these cases.’’

The Pentagon reported to Congress that from September 2010 to September of last year, there were 3,192 reports of sexual assault — which included both victims and those accused of assault.