The Military is Leaving the Missing Behind (opens in new tab)

Seems a minor cost compared to a life, or thousands of lives.

Not because they're particularly dedicated to helping out constituents, although many are, but because it's great for re-election. A good congressional district staffer could take this, write up a few letters "from" the Congressperson to whoever's in charge of the person in charge of JPAC, send a release to the local cable channel, and get a pretty good local firestorm going on the issue to shame the DoD into some action. This may not get the investigation going, but it will get some progress...which will be good for the petitioner (since they got some official attention they wouldn't otherwise have), and good for the Congressperson (since they'll be able to highlight this in their newsletters and when they're running for re-election as someone who "gets results"). District staffers live for things like this; take advantage of it.

Pro tip if you have something where you're going to use this strategy: make it as easy and as obvious as possible what you'd like your representative to do. Want them to send a letter to a particular official? Attach a copy of the letter you've already sent that official. Want them to make a call? Include all the information you have about the person you tried to call, their supervisor's information, and the talking points you would have used had you been able to make it. Keep your issue morally black-and-white, and make it very easy to understand how doing X will result in something concrete and simple that the representative can consider an accomplishment. You're competing with a whole host of other interests who want some of this representative's district time, so make it very clear why what you want is easy to do, morally right (according to the morals of the majority of your district), and simple to understand & be convinced of.