DALLAS (CBSDFW.COM) – Officials in Dallas have identified the masked man who they say opened fire at the Earle Cabell Federal Building in downtown Dallas.

The FBI says Brian Isaack Clyde, 22, was killed after a gunfight with federal officials outside the building.

As a result of the investigation, streets around the courthouse will remain closed for the next couple of days.

The FBI in Dallas tweeted, “According to federal authorities, the Earle Cabell Federal Building located at 1100 Commerce Street in downtown Dallas will be open for employees Tuesday, but not for business. That means no hearings or public services.”

Dozens of Dallas Police Department squad cars and emergency vehicles from Dallas Fire-Rescue were on the scene after the active shooter situation at the building in the 1100 block of Commerce Street.

More than 300 federal employees were in the building during the incident.  One employee suffered minor injuries as she was taking cover from the shooter, according to U.S. Attorney Erin Nealy Cox.

FBI Dallas Special Agent in Charge Matthew DeSarno explained, “Shortly after the incident began this morning officers from the Federal Protective Service engaged the shooter Brian Isaack Clyde. He was taken to Baylor hospital and pronounced deceased on scene.”

Clyde was discharged from the Army in 2017.

“Private 1st Class Clyde served as an infantryman in the Army from August 2015 to February 2017,”  according to the Army Public Affairs Office.

The FBI said he was not the subject of any investigations up to Monday’s shooting.

FBI agents are deployed across the state, speaking to relatives and associates and trying to get to the bottom of what the motive was.

“He had more than five 30-round magazines on his person. That’s a lot of rounds at his disposal. A large powerful weapon at his disposal,” said DeSarno. “As far as what he was trying to do, we don’t know that yet completely. We’re reviewing videos. But for the actions of the federal protection office this likely would’ve been a deadly incident.”

U.S. Attorney Cox wanted to calm the fears of those in the area. “The federal building was shot on by an active shooter,” she said. “Law enforcement responded immediately and I want to assure the community, especially our downtown community, that the community is safe.”

Video captured on cell phone by Dallas resident Tim Brown shows a masked person outside, armed with some type of long-rifle, firing near an entrance to the building. Bullets shattered panes of glass in a revolving door of the building. The sounds of gunshots can be heard and smoke can be seen coming from several feet away, as the gunman runs across the street into a parking lot and collapses.

Clyde was given medical attention at the scene and then taken to a local hospital where he was pronounced dead.

Clyde’s vehicle was found nearby and a police bomb squad examined it “for precautionary reasons.” Several minutes after examining the car with a robot police decided to perform a controlled explosion of the vehicle.

After the shooting, witness Don Myles told CBS 11, “I just saw a burst of people running out and a round of shots. It was just shots, maybe 10 to 15 shots all rapid shooting, and I just ran across the street into the traffic.”

Downtown Dallas Residents Ducked For Cover, Recorded Video Of Federal Courthouse Shooting

All of the streets surrounding the federal building — Commerce, South Field, Jackson and South Griffin Streets have all been closed.

Because the shooting happened on government property, the investigation has been handed off to the FBI. They will be assisted by the ATF, Federal Protective Service, U.S. Marshals and the Dallas Police Department.

Clyde graduated from Del Mar College in Corpus Christi in May 2019 with an Associate in Applied Science degree in Nondestructive Testing Technology, the college confirms.

Dallas ISD confirms Clyde attended Woodrow Wilson High School as a freshman. He withdrew March 1, 2012 when his family apparently moved.

The FBI asking people who recorded events connected with the shooting to send them in.  Anyone with information or video should call 1-800-CALL-FBI or submit information, video and tips online here.

Newly-sworn in Dallas Mayor Eric Johnson released the following statement on the shooting:

“I have been briefed by Chief Hall regarding the shooting at the Earle Cabell Federal Courthouse this morning. I am glad no civilians or officers were harmed, and I commend our law enforcement for their swift response to contain the situation.”