The job of an investigative journalist is often hard work, stressful and requires a huge amount of determination, but it can also be incredibly rewarding.
These journalists play an important role in the upholding of a just democracy - in fact, their investigative work can often be the only way of uncovering information about topics of public interest.
Award-winning BBC reporter John Sweeney explained that determination, skepticism and persistence are crucial skills for those looking to enter the profession.
The most satisfying stories are those that powerful people don't want the public to know about, he said.
Reporting for programmes such as Panorama and Newsnight, Sweeney has traveled undercover to gain unprecedented access to North Korea, confronted Russian president Vladimir Putin over killings in Ukraine and helped free many innocent mothers from jail sentences that convicted them of killing their children.
He told Journalism.co.uk that one of the best things about his job is that he is able to "supply a voice to the voiceless", but explains that the job comes with a range of moral responsibilities that one must adhere to, in order to prevent exposing the wrong people or "getting into trouble".
Additional footage by BBC Panorama.