Investigative journalism is a form of journalism in which reporters deeply investigate a single topic of interest, such as serious crimes, political corruption, or corporate wrongdoing. An investigative journalist may spend months or years researching and preparing a report. Practitioners sometimes use the terms "watchdog reporting" or "accountability reporting".
Most investigative journalism has traditionally been conducted by newspapers, wire services, and freelance journalists. With the decline in income through advertising, many traditional news services have struggled to fund investigative journalism, due to it being very time-consuming and expensive.