The seventh in a lineage of FBI directors with law degrees, James Comey has shaped politics in the US as the head of the law enforcement agency. But who is the man behind the headlines? From prosecuting an American celebrity to refusing to sanction the NSA's mass surveillance program, DW explores the contentious life of James Comey.

Serving as Manhattan's chief federal prosecutor, Comey rose to notoriety in 2002, when he led the prosecution of US celebrity Martha Stewart for securities fraud and obstruction of justice. Stewart, widely known in the US for her cooking and lifestyle shows, served a 5-month jail sentence following the highly-publicized case.

In late 2003, Comey was confirmed as the US deputy attorney general, making him the second-highest-ranking official in the Justice Department. Serving under former President George W. Bush, Comey endorsed a memorandum approving the use of 13 enhanced interrogation techniques during the War on Terror, including waterboarding. He later said he lobbied to have the policy toned down.

Comey has warned of the consequences of domestic mass surveillance, saying in March: "There is no such thing as absolute privacy in America." While serving as acting attorney general during the hospitalization of John Ashcroft in 2004, he refused to endorse the legality of the NSA's domestic surveillance program, even when pressured by the Bush administration.

In 2013, then-President Barack Obama nominated Comey to serve as the seventh director of the FBI. He received the nomination despite being a registered member of the Republican party. Later that year, he received congressional approval to takeover the office. In his installation speech, he said the bureau's work is founded on integrity. "Without integrity, all is lost," he said.

In 2015, Comey penned an op-ed on why he required new FBI special agents and intelligence analysts to visit the Holocaust Museum in Washington. He said the reason was to have them understand the consequences of abusing power and to be confronted by the atrocities humans are capable of. "I believe that the Holocaust is the most significant event in human history," he said.

In July 2016, Comey announced that the FBI had found no evidence of criminal intention in Hillary Clinton's use of a private email server as state secretary. But days before the presidential election, he issued a letter to lawmakers informing them of new emails deemed "pertinent to the investigation." He later said no evidence was uncovered. Clinton has since blamed Comey for losing the election.

On May 9, Trump sent Comey an unusual letter firing the FBI director, cutting short his 10-year mandate to lead the bureau. Given the ongoing FBI-led investigation into election-meddling by Russia, critics have warned that the move may amount to obstruction of justice for undermining the probe. Trump later appeared to threaten Comey over the existence of "tapes" of their conversations.

Comey reportedly kept memos of interactions between him and President Donald Trump, which appear to implicate the head of state in attempts to obstruct a federal probe into Russia's alleged involvement in influencing the 2016 election. The day after US media reported on the existence of the memos, the Justice Department named a special counsel to lead the probe amid fears of White House influence.

In June 2017, shortly after being fired, Comey testified in Congress that he believed Trump fired him over the Russia probe. "I was fired in some way to change, or the endeavor was to change, the way the Russia investigation was being conducted," he told lawmakers. He has since released a book, in which he described Trump as a "mafia boss" who is "untethered to the truth."