It depends on what crime they believe and can try to prove was committed.
Do they believe it was murder? Was it rape? Was she alive when taken away?
If she was alive? That is abduction.
On the other hand, you have a friend over and she dies from a drug OD.
You put her in your car, take her to Indianapolis and dump her in the White River. This is not a Federal Crime. But, there is a State Crime called Abuse Of a Corpse. It is a minor felony if you can prove someone had sex with a dead body or mutilated the corpse. But, if you have dumped an intact body, I'm not sure you will face a criminal penalty in Indiana. At least, not much of one.
But now I must argue that drug OD does not make sense. So, now let's play you are a drug dealer. You must hide the girl because you don't want them to determine there are drugs in the body that you gave her. So, you hide her, yet leave a bag full of white powder in her room. This just does not make sense because you could have access to that room to clean up because all POI are friends of the roommate. One would not hide Lauren because of a drug OD, yet leave the drugs they supplied in her possession.
I'd bet the bag was planted because friends of Lauren insist she was not into hard drugs just a few weeks before she disappeared. And, one does not start with coke by buying by the bag full.
This story contains a great lie which we must disprove to get justice for Lauren. Someone must believe a crime was committed.