The source where you might expected to find biased information is CANDIDATE'S WEBSITE.
A biased information is an information that has a preconceived opinion about something or someone. The biased information may be in favour or against the person.
The principal reason why a candidate will set up a website is to sell himself and persuade people to vote for him. Information found on such a website will strongly favor the candidate and will present him as the best person to vote for. Such information will be strongly biased in favour of the candidate.