Star Trek: 10 Things You Didn't Know About The Bell Riots
4. No One Is Simply One Thing
Biddle Coleridge, or BC (named in honour of DS9 assistant director B.C. Cameron), was played by Frank Military in Past Tense. He is a 'ghost,' one of the residents of the Sancutary Districts that leaned toward violence. He is introduced as an unpleasant person hassling Sisko and Bashir, though later is shown murdering Gabriel Bell in a scuffle. He takes the processing centre hostage, coming face to face with Sisko, now claiming to be Bell.
It would have been easy to write BC as a stereotypical thug who uses murder as a means to an end. However, Behr was insistent that they needed to make him something more. BC murders Bell in Past Tense Pt 1, and the murder isn't discussed at all in Pt 2.
As Behr comments in the DS9 Companion:
We didn't want the crux of the thing to be 'Sisko trapped with a murderer'...he wasn't inherently a murderer
Behr and the writing team crafted a large backstory for BC which, though little of it was seen on-screen, explained what drove him to commit his crimes. He would have been something like a mechanic in his former life, down on his luck, forced into this District, and left to fend for himself. Not defining him as murderer was something that Behr was very proud of.