If you fail to account for office rent, his car, the garage, the mechanics in the garabe, the gasoline, and so forth, you'll end up not having enough income to pay to have one.
One should only ever look at directly attributable costs, because those are the costs, those are ALL the costs.
I didn't throw out office rent (though most cops on the beat don't have an office per se, they get a desk in a bullpen), the car, the garage, the mechanic or the gas. I threw out the 3 other cops you tried to add and any major cost in the legal system because a petty theft charge isn't going to draw major costs in the legal system. Shoplifting cases fly through the legal system fast, less than a minute a piece for the 99% of them that don't get contested, the largest sink of man hours is from the cop himself who has to fill out the initial paperwork which takes a while, unless it's contested everybody else rubberstamps it.
And remember most police departments like these kinds of crimes, because they're fast money for the department. Individual cops tend to hate them because they don't consider it real police work, but the department loves them because they bring in more revenue than they cost. If they didn't bring in more revenue than they cost then they'd up the fines. That's why so many cops get assigned to traffic detail, handing out tickets for $150 or so that rarely get contested is a revenue generator.