Diehl-Armstrong, already in prison for a slaying two weeks before Wells' death, has denied involvement in the plot. And Wells' sister, Jean Heid, supported her claim before Diehl-Armstrong was sentenced.
Heid reiterated the family's belief that Diehl-Armstrong was just a pawn and that Wells wasn't a co-conspirator, as federal prosecutors allege.
According to prosecutors, they were assisted by William Rothstein, Diehl-Armstrong's ex-boyfriend, who built the bomb collar using two egg timers she provided and helped force Wells - who prosecutors say may have gotten cold feet - to wear it.
Rothstein was drawn into the case when he called police in September 2003 to report having the body of James Roden, 45, in his garage freezer. Diehl-Armstrong later pleaded guilty but mentally ill to third-degree murder - and is still serving her seven- to 20-year sentence for his shotgun killing 18 days before Wells died.
Police stopped Wells' car shortly after he took $8,701 from the bank, and he sat handcuffed on the pavement as officers took cover while waiting for a bomb squad.
"All the more haunting to us were Brian's last words caught on the (local TV news) video tape," Heid said. "'I don't have a lot of time. It's gonna go off. I'm not lying. When is someone gonna come and get this thing off of me?'"