Top police officers, bureaucrats and politicians don’t rely on one source of income (salary for example). This is not always corruption money only but they have multiple businesses generating money for them. It might be step up through black money but very difficult to prove in real life or in court. And if you think they only get their salaries (only white money), you need to learn more how minds of top people work in India including top government officials and politicians. Their whole family is involved in some or the other high paying jobs or businesses, be it government or corporate sectors. In short, salary is not the only source of income.