Rep. Mike Turner, R-Ohio, said he is investigating the answers provided by the U.S. Marine Corps in response to the rape and slaying of Lance Cpl. Maria Lauterbach near Camp Lejeune, N.C.

She filed rape charges against Marine Cpl. Cesar Laurean in April 2007. Investigators found her body buried in his backyard Jan. 11 and an autopsy revealed she was eight months pregnant at the time of her death.

"There is a belief that the culture in the military does not adequately protect women or take this issue seriously," Turner told Cox news service.

Sens. Johnny Isakson, R-Ga., and Lindsey Graham, R-S.C., are working to develop legislation that would apply the Uniform Code of Military Justice to sexual assault and other violent crimes in combat zones where normal legal jurisdiction may not apply.

The Defense Department has an office handling sexual assault claims, but said it would only refer victims of sexual assault to medical officers if the case involved civilian contractors in a war zone.

Defense Department records show a 24 percent increase in sexual assault claims from 2005 to 2006.