Base salaries are often only $100k but then generous vacation compensation, incentives, 2x and 3x overtime, and such bring it close to $200k. Gold plated health and other benefits often bring current compensation for CA cops (CHP, BART, SF, &c) over $200k.

Then generous pensions kick in. CA cops and firemen usually get full pensions after 20-25 years but the pension is paid not just on salary but a multiple of final year vacation and comp time. Pensions can be 2x-3.5x final 'base' salary and higher than any overtime adjusted salary. CalPERS is hoping for 5% above inflation returns but for a decade has made about 1%. At 1%, you essentially have to save or take on future liability for the whole pension during working life. No private employer provides these benefits after 20-25 years or on this basis at all because it would mean bankruptcy.

Public finance allows it so the total compensation of a cop getting $200k in salary, adjustments, and benefits is often over $500k all in. Some of that will be the bankruptcy and bailout.

Google "Vallejo firefighter bankruptcy" for details of CA's future public safety service.

Maybe from working side jobs? Most police departments offer a ton of various side jobs. Be it renting out officers to basically do security for various businesses, or working at understaffed or undesirable locations. These jobs usually pay really well, sometimes between 60-80 dollars an hour.

I have no clue if this extra pay would be shown in city salary databases, but I wouldn't be surprised if not.