In my story someone running for govenor has hired public relations people or he uses a public relations firm. They try to find things on his opponent to use in negative ads.
Is this realistic? If he does hire them, what might be their duties?
Answer Public relations firm doesn't do that kind of work. There are full-time "background checking" companies that will bring up all marriage, divorce, public reecords, etc. for a person in a particular county/state.
They will research all available credit, business, criminal, military records, and if the individual has been a public figure, his voting record, his attendance record, who his conributors are, where he spends his vacations, where he lives, how many houses, yachts, stocks, etc. he owns, and how he/she made their money.
If something good comes up, he can then hire private investigators to interview people, and/or follow the target around.