Here is a site dedicated to Budd Dwyer, where you can also find the video and details on what happened that day and why he did what he did.

Basically he was a tragic figure who was about to have his entire career and lifetime of work destroyed because of a bribery scandal. I believe the man was innocent, because no guilty person would kill himself after vehemently denying the charges. Yes he could have served his sentence and lived the rest of his life in seclusion and still retained his innocence, but he did it so that his family would collect his pension which he would have lost as soon as he was stripped of his position.