Answer:
The term muckraker refers to reformist journalists who wrote predominantly in the US journals of the early twentieth century. It is related to research journalism, sensationalism and vigilant journalism. The Watergate case is an example of this.
They exposed social ills, dirty business, nepotism and corruption in business and politics. Former US President Theodore Roosevelt referred to these journalists as muckrakers, after a character in John Bunyan's The Pilgrim's Progress, Man with Muckrake, who scrapes the animals' dung from a stable.