What did Sanders do to become a felon?
In the course of investigating the cover up of the crash, he persuaded someone to appropriate a swatch of the seat covering from the area of the plane where he believed the missile penetrated so he could have an independent analysis performed to see if any propellant or explosive residue was present.
clinton had him, and his wife, prosecuted under the law forbidding the removal of debris from a crash site, despite the fact that James Kalstrom had given away parts of the plane to survivor's families as a (political) symbolic gesture.
The Sanders' prosecution was clear act of intimidation and an attempt to silence them and suppress their book "The Downing of Flight TWA 800".
Check it out.