Mary-Kate Olsen is off the hook. Investigators have dropped their probe into where Heath Ledger got the pills that killed him.

The U.S. attorney's office in Manhattan was overseeing a Drug Enforcement Administration investigation into whether the painkillers found in Ledger's system were obtained illegally, but the prosecutors have bowed out "because they don't believe there's a viable target."

What, they can't reach an Olsen twin?

Now, we may never know if Mary-Kate had anything to hide in the death of "The Dark Knight" actor! Don't get me wrong, I love M-K and Ashley just as much as the next queen, but you know something was up and asking for immunity didn't help speculation.

It doesn't matter now, though! Mary-Kate is good to go.