The two other parts of the belief system in Probable Cause are Burden and Hunch.
Burden

Nick Nolte as the cop in 48 Hours.
Burden is something in your character’s life that is a burden or a stress factor, or even a personal goal. For extra tension, make up a Burden that’s perpendicular to the ongoing case. This could be a beginning separation with your spouse, who gets what and what about the kids etc. It could be a deep and overwhelming debt problem, a career thing, illness or dependency on drugs, or something form the character’s past coming back to haunt her. Playing towards your Burden earns you a Destiny point reward, and should your character reach a point where her Burden is “solved” it earns another Destiny point reward.
Burden should include a statement, an action and a target.
“I might be broke, but I’m not selling the house to get money for my alimony payments to my ex-wife. There’s gotta be another way.”
“I can’t go back home after what Mary did – I end up in bars every night and pick up women. Any woman will do, I just don’t want to see Mary again.”
Make it possible for you to show in play how your character is reacting to or trying to deal with her Burden – it earns Destiny points.
Also, make sure you choose a Burden you want to be challenged, because the GM will do that, all the time, during the game.
When a Burden has been overcome, take some time to stop and think. You can either retire the character from play and create a new one, or write up a new Burden. Your choice.
Hunch
Hunch is your character’s habit or usual reaction. From The Wire, it’s Bunk’s pinstripe suit, his cigar or his chasing tail. Or McNulty’s quarter of Jamieson in his pocket. From The Killing, it’s Sarah Lund’s sweater, her sensing of a crime scene, or her inability to connect with other people. From Twin Peaks, it’s agent Cooper recording every detail of his working day for Diane, his obsession with coffee and doughnuts and pie. It’s Andy breaking into tears when he sees a dead body. All these small, quirky details about a character adds dept and hopefully interest. Feel free to come of with weird stuff you don’t even know the explanation to yet. Perhaps your character’s gun has a pink grip. Or she has a tattoo on her belly that says “HANK”. Or she always wears leather pants on Fridays. Or can never get the fax machine to send.
Playing out you character’s hunch earns you a point of destiny. You are even rewarded when you decide to go against your character’s hunch if it makes a situation more difficult. This way you can enable your character to be more efficient in the fiction, when you need it or think it’s dramatically appropriate, all depending on how you choose to play the character at any given moment.