Brian Babbage was the eldest of three children, all of them potential heirs to their late father's very substantial fortune. Their father, either out of senility or just pure spite, changed his will constantly before his death, laying the ground for a very nasty legal battle between the three siblings, each of whom had enough to hire a battalion of lawyers. While Brian's younger brother Ricky and his sister Amanda eventually agreed to a settlement, Brian refused, believing that he was entitled to a much larger share. Eventually, he decided to kill his siblings so he could keep it all.
Brian came up with an ingenious way of sending mail bombs while giving himself a cast-iron alibi: he broke into several mailboxes and glued a package bomb to the top of the compartment, so that they would not be collected until several months later, when the glue failed and the packages dropped down to join the rest of the mail. To strengthen the appearance of his innocence, Brian also mailed a third bomb to his own home, to make it seem as though all three siblings were being targeted.
His planned cast-iron alibi was to be in jail, and therefore incapable of mailing anything at the time the packages were collected and postmarked. So, in May of 2003, he rammed his Mercedes into an unmarked car being driven by Lieutenant Disher and Captain Stottlemeyer, yelled at them to "kiss my ass!", gave them the finger, and took off (beforehand, he had even selected a terrible criminal defense lawyer, to ensure that he would be jailed). What he didn't plan for was getting hit by a truck during his getaway, sending him crashing into two other cars, cracking his skull, and putting him into a Stage 9 Coma for four months.
Unconscious, and hovering near death, he couldn't appreciate that he had lucked into, to quote Adrian Monk, "the best alibi in the history of crime." While he was asleep, one of his bombs succeeded in killing Amanda, but, thanks to Monk's quick thinking, the other two bombs failed to hurt anyone.
He regained consciousness in August, 2003, after a mishap with Monk, who was visiting his room, inadvertently unplugged his respirator and then had to revive him with CPR. Unexpectedly, the experience jump-started Brian's brain, and he woke up.
Told that his brother and sister had both been killed, Brian faked grief, while inwardly dancing with glee that he was home free, and rich. Then his house maid brought by what looked like one of his parcels, partially opened. Brian panicked and dived to the floor, shouting that it was a bomb - something only the bomber would have known. He was arrested for Amanda's murder (and probably severely disappointed to learn that Ricky was still alive, and thus the sole heir).