Suppose it is two days before a murder trial, and a criminal case has recently been weakened by the suppression of valuable evidence. Without this physical evidence, the prosecution rests upon a witness who simply heard gunshots and saw a group of men scattering—hardly a fool proof case that one of the scatterers was the gunman. The prosecutors can and should dismiss the case pretrial, knowing they lack sufficient evidence to convict.

But fearing such a high stakes loss, the prosecutor concocts an idea. His earwitness is young, uneducated and highly impressionable. He will simply coerce this witness to take the stand and lie. Under his pressure, the witness will claim to not just hear gunshots but to see the chosen suspect fire the murder weapon.