Prosecutors brought an indictment alleging that former Deputy Mayor Raymond Chan, while working for downtown developers, set up a job for the family member of a city commissioner; had his company hire a relative of a City Council aide; and proposed a fake consulting contract with another city staffer’s mother. Such job offers, even modest ones, were a way of greasing the wheels of the city bureaucracy, prosecutors allege. Experts say indirect bribes can be more difficult to uncover than a typical quid pro quo in which someone gives money directly to a government official. In one example, prosecutors accuse...