The Secret Service, the law enforcement authority that protects the White House and the president, indicated earlier on Twitter that the incident appeared to be a suicide.
The District Capital Police Department reported their natural death squad was on the scene and will continue to provide updates.
The Secret Service first said it was responding to reports of a self-inflicted shooting along the White House's north fence around noon.
The deceased had been identified by Secret Service and DC Metropolitan Police, but his identity was being withheld until his family was notified.
Reporters at the White House tweeted about sheltering in place.
President Donald Trump was at the so-called Winter White House, his Mar-a-Lago resort in Palm Beach, Florida, when the incident occurred.
According to U.S. media, Trump has been briefed on the incident and is set to return later today.
Police and medical personnel quickly swarmed the area, and the White House was placed on lockdown. The White House says Trump has been briefed on the shooting. A Secret Service source confirmed to CNN that the suspect's auto was located in the area where the search of the vehicle took place. A Tennessee woman intentionally rammed her vehicle into a barrier outside of the White House on February 23.