Defense Secretary Jim Mattis expressed alarm last week at reports of failures to address a growing problem of sexual assaults on military bases among dependent children and teens.

"That, to me, is something that must be rooted out. It's important we stand up and say what we stand for. On this one, it's even more important we say what we will not tolerate," he said at a Senate Defense Appropriations subcommittee hearing last Wednesday.

Mattis made the comments in an exchange with Sen. Patty Murray, D-Washington, who cited a March investigation by The Associated Press that found nearly 600 cases since 2007 in which dependent children were sexually assaulted by other children on military installations and in Department of Defense Education Activity schools.

Murray said that more than 30 of the nearly 600 cases were in her home state of Washington "and just recently, the Army released information on 86 additional cases."

"Even more shocking, it appears that these children and their families have no recourse" since dependent children do not come under military law and there can be jurisdictional problems with local civilian authorities, she told Mattis.

Murray said she had written a detailed letter to Mattis in March asking "some straightforward questions about the scope of the problem and the department's response," but had yet to receive an answer. "So I'm concerned that the department is not taking this seriously."

Mattis said he wasn't aware of the letter but promised a quick response. "Senator, first of all, you'll have an answer within the week. I was unaware of that, but thank you for bringing it up."

He said the military has to accept that casualties will occur on the battlefield, but "I do not accept a single casualty in the Department of Defense out of sexual assault. That is intolerable. So I don't know if it's a unique problem to us" but "how do we stop it is the bottom line."

Murray interjected: "Well, that's what I wanted to ask you, who has legal jurisdiction over military children on the military installations both here and abroad?"

"Let me get back to you specifically because I think it's also different depending on where it's located," Mattis said, but "we will get back to you with the full answer."

In her March letter to Mattis, Murray said the AP investigation "reveals an inscrutable system that fails these children at every level: Military investigators do little to follow up on reported assaults; federal prosecutors are loathe to pursue juvenile sexual assault cases; and local authorities rarely have the capacity to take on these cases."

According to the AP investigation, the documented cases of sexual assaults among children on military bases showed that they can occur "anywhere children and teens gather on base -- homes, schools, playgrounds, food courts, even a chapel bathroom. Many cases get lost in a dead zone of justice, with neither victim nor offender receiving help."

-- Richard Sisk can be reached at Richard.Sisk@Military.com.