WASHINGTON — New York police detective Keith Schiller was at the Manhattan prosecutor’s office for a meeting one day more than 18 years ago when he spotted a local celebrity: Marla Maples, Donald Trump’s second wife, who was there to discuss an alleged theft by a former employee.

A guy sat down next to him and was introduced as Maples’ bodyguard.

“I looked at him, totally not impressed by his stature, physical stature,” Schiller recalled in a 2015 videotaped interview about how he came to work as a security officer for Trump. “... A light goes off. I said: ‘Bodyguard, I can do this’ ... I’m no stranger to putting my hands on people.”

Now with Trump in the White House, Schiller sits at a desk just steps away from the president as director of Oval Office Operations. He serves as one of Trump’s most trusted aides — as well as a key player in this week’s controversial firing of FBI director James Comey.

On Tuesday, the president personally dispatched Schiller to FBI headquarters to deliver a letter informing Comey he was “terminated” — a moment that was recorded and broadcast by CNN. Trump chose Schiller for the task over a more junior staffer, one White House official said.

That a person with Schiller’s profile is now a senior White House aide with near round-the-clock access to the president is just one more way in which the Trump White House has broken with norms set by previous administrations.

“The president has exceptional confidence in Keith. If he asks him to do something, he knows it will get done,” said Corey Lewandowski, Trump’s former campaign manager who worked closely with him.

Schiller has long been critical of Comey, telling those around him that the FBI was not aggressive enough in its investigation of Hillary Clinton’s use of a private email server and his views helped shape those of his boss, according to a person close to Trump who requested anonymity in order to talk about internal deliberations. Schiller remains in touch with many law enforcement officers and has often served as Trump’s liaison with police departments.

He has also repeatedly gotten physical on Trump’s behalf, punching a protester outside Trump Tower, forcibly removing a reporter from a press conference and confronting many who interrupted Trump’s rallies.

In a young White House that is considered one of the leakiest in history, Schiller has become one of the few people that the president can talk with and know that their conversation will not be repeated to others. White House officials often look to Schiller for tips on the president’s mood or how best to approach him.

“Keith Schiller is not just some bodyguard,” said Michael Caputo, a political adviser who worked with Trump between 2013 and 2016. “Nobody knows the score among the advisers better than Keith Schiller. ... Keith’s always known what’s what among the people who are in Donald Trump’s orbit.”

When Trump’s son-in-law Jared Kushner traveled to Iraq in April, Schiller came along — getting a seat at the table during talks with the Iraqi government, standing in group photos and hovering in background of photos of Kushner. Iraqi specialists in the government who typically would participate in such trips were not included, being told there wasn’t enough room for them on the plane.

Schiller turns down most interview requests — including one for this story — although he agreed to be interviewed on New Year’s Eve 2015 at Trump Tower by Rich Siegel, a high school friend. The 55-minute conversation was posted on Facebook and provides a rare narrative of Schiller’s years-long relationship with Trump.

After seeing Maples’ bodyguard at the Manhattan District Attorney’s Office, Schiller reached out to Trump and started working for him part-time in 1999. In 2004, following his retirement from the police department, Schiller became the Trump Organization’s director of security. Schiller followed Trump onto the campaign trail, providing security in the months before the Secret Service took over — and then continuing to provide an added layer of protection, not hesitating to keep reporters away from the candidate or venture into rally crowds to confront protesters, sometimes physically.

Some who have worked with Schiller gushed as they described him, painting a softer portrait than the image of the imposing 6-foot-4-inch bodyguard with closed-cropped hair and an often stern demeanor.

Eric Trump, one of the president’s sons who worked with Schiller for years at the Trump Organization, described the bodyguard as someone who has “always demonstrated incredible work ethic and loyalty.” Lewandowski described Schiller as “the guy you want next to you in the foxhole when things go badly.”