The family of a Wisconsin soldier killed in Iraq last week expressed gratitude Tuesday for the outpouring of support it has received, and said no decision has been made on whether her two sisters, also stationed in Iraq, will return there.

Spc. Michelle Witmer (search), 20, of the 32nd Military Police Company (search), died when her Humvee was attacked in Baghdad.

Michelle's 24-year-old sister, Rachel, serves in the same military police unit, while Charity, Michelle's twin sister, was sent to Iraq late last year as a medic with Company B of the Wisconsin Guard's 118th Medical Battalion.

"We are conflicted because we have two families and we can't be with both at the same time," a statement read by family spokeswoman Joan Apt on behalf of the sisters said.

Defense Department policy states that if a soldier dies while serving in a hostile area, other soldiers of the same family are exempt on request from serving in a hostile area. That request must come from the soldiers themselves.

"Rachel and Charity would like to express to their fellow soldiers in the 32nd MP Company and Company B 118th Medical Battalion our thoughts and prayers are with you," the statement said.

The surviving sisters, their two brothers and their parents, John and Lori Witmer of New Berlin, stood by as the statement was read at Elmbrook Church, but did not answer questions.

Lt. Col. Tim Donovan, a spokesman for the Wisconsin National Guard (search), said the sisters will decide whether to return to Iraq when they are comfortable.

"We've given them no timetable," he said. "They're on 15 day leave that ... could be extended a day or two. I'm sure it's a tough decision for them. We all stand behind them whatever the decision will be."