Law & Order: Special Victims Unit - Season 7 Episode 16 : Gone

Doug Waverly and Nick Pratt are charged with rape and murder in the disappearance of Canadian student Jennifer Durning after Nick's cousin, Jason King, claims that while he had consensual sex with her that night the other two raped her. A stray pubic hair leads Novak to Keith Willis, a drunk who was paid off by the boys to get Jennifer out of the hotel and who later saw the boys kidnap her, but Willis exactly fit to be a witness as his mind has gone after years of alcohol abuse. Jason King disappears. Although they are able to find a bug in Donnelly's office, they are not able to prove that it was placed there by Pratt or Waverly. Judge Donnelly is forced to dismiss the case against the two boys since there is no case without Jason's testimony.