Veteran FBI agent Gerald Rogero was found guilty Friday of second-degree assault after he was captured on cellphone video striking a 15-year-old boy during a domestic dispute in Chevy Chase, Md. (Montgomery County State's Attorney's Office)

The cellphone video — which would be played repeatedly for jurors — showed a rapidly deteriorating situation outside a high-rise apartment building in Chevy Chase, Md.

In the middle of the turmoil was FBI agent Gerald Rogero. He was off duty at the time, wearing civilian clothes, and had just struck a teenager in the chest, sending him backward onto the pavement. The teen got to his feet.

Rogero moved to place him under arrest.

“If I have to shoot you, I will,” he said. “Don’t make me shoot you.”

The video and the audio that went with it were at the heart of the prosecution of Rogero, 46, an agent for nearly 20 years who serves as a chief in the FBI’s counterterrorism division.

He was back in Montgomery County court Tuesday after being found guilty last week of second-degree assault. A jury acquitted him of a more serious first-degree assault count and a gun charge. The split verdict, arriving after about five hours of deliberations, suggested that jurors thought Rogero had acted illegally only to a point — when he improperly shoved the teenager. After the teenager got to his feet, and he and Rogero began wrestling, the agent was within his rights to pull a gun out of his ankle holster, point it at the youth and order him to the ground.

“We get to watch it on TV,” Rogero’s attorney, Marlon Griffith, told jurors before they rendered a verdict. “He lives it.”

Christopher Allen, an FBI spokesman, confirmed Tuesday that Rogero remains on active duty. He said that the bureau is conducting an internal review of the incident but that he could not comment further because the issue is a personnel matter.

The Dec. 5, 2014, altercation arose from a child custody drop-off.

Rogero was visiting a friend who was expecting to take custody of her 1-year-old daughter. The girl’s father arrived late with the child for the drop-off, starting the friction. Rogero and the teenager were among a group of people on hand for the exchange as it went from testy after the father’s late arrival to belligerent, the video shows.

Rogero, his attorney and prosecutors returned to court Tuesday to finish up two matters left hanging after the verdict was announced Friday.

Moments after he heard the jury’s decision Friday, Rogero appeared as if he were about to faint and was taken by ambulance from the courthouse.

The Tuesday court session was held to set a sentencing date and argue whether Rogero should surrender his weapons.

Circuit Judge Steven Salant set sentencing for Jan. 20.

Assistant State’s Attorney John Lalos then argued to the judge that Rogero should surrender his weapons — an FBI-issued service handgun and his personal handgun.

“At the end of the day, we are here because of the defendant’s conduct, off duty, while armed,” Lalos said.

Rogero’s attorney, Griffith, said that since the charges surfaced 11 months ago, Rogero has been allowed to carry a weapon. And he cited the outcome of the trial, when jurors acquitted his client on the charges that involved having a gun unholstered.

“It’s clear that in order for him to continue to be an FBI agent, he needs to be armed 24 hours a day,” Griffith said.

He indicated he will seek a sentence that would allow his client to remain on duty.

Salant, who presided over Rogero’s trial, sided with Griffith. He said Rogero is entitled to make arrests and react to emergencies.

“I would not want to take that away — if in fact the public, in an emergency, needed his services,” Salant said in court.

The trial last week centered on a three-minute stretch shortly before 11 p.m. in early December. The video clearly showed the agent striking the teenager with force, but the recording had its limits. The narrow borders didn’t capture actions to the left and right of the frame. At times, people were talking over each other.

That left moments up for interpretation and, during the trial, allowed each side to say that the video supported its arguments.

“The defendant creates this situation,” Assistant State’s Attorney Mary Herdman told jurors in closing arguments. “The defendant is the aggressor in this situation, from the jump, and we see it on the video, which you guys have watched over and over.”

She suggested that Rogero, who testified, told jurors self-serving recollections of what was said just before the assault. “He has had 11 months to review this video, fill in the gaps, figure out what’s going to be most helpful,” the prosecutor said.

During his testimony last week, Rogero talked about trying to arrest the 15-year-old and threatening to shoot him. “It was a subconscious thing that I said,” he recalled, saying he spoke the words “to get him to comply with what I was asking him to do.”

Griffith said images and key moments in the video confirm that the agent faced an “imminent threat” from a mouthy teenager. “Thank God for video,” he said during closing arguments. “Thank God for video.”

After depicting the confrontation, the video shows the 15-year-old lying face down on the sidewalk. Things start to calm down, and a Montgomery County patrol officer arrives.

John McCarthy, the top prosecutor in Montgomery County, said the case was important to pursue. “You must honor your obligations under the law, and that’s what we did,” he said. “I think the video speaks for itself.”

The video captures how tension quickly rose after the father walked into the apartment building’s lobby, holding the child. Both sides were soon talking about calling the police. It is unclear whether anyone knew that Rogero was an FBI agent.

“You’re already two hours late,” Rogero said to the father, identified in court records as Edward Moawad.

Moawad gave the girl to the child’s mother. He walked outside. His girlfriend and her children also could be seen.

Rogero also walked outside and told Moawad he had been disrespectful by showing up so late. Moments later, Rogero turned to someone in the small crowd and said, “You’re going to get yourself locked up, so don’t act so stupid.”

At this point, the 15-year-old boy, wearing a red sweatshirt, walked up close to Rogero, standing about 18 inches away. It was unclear on the video what he said. During the trial, Rogero would testify that the teenager used vulgar terms to say he was about to attack.

Rogero suddenly struck the teenager with the heel of his hand, sending him reeling backward.

The agent turned to someone else. “You going to get in front of my face?” he said.

He turned back to the teenager, who had gotten to his feet. “You’re under arrest,” he said. “You’re under arrest right now.”

Rogero tried to get him to the ground. “If I have to shoot you, I will,” he told the boy. “Don’t make me shoot you.”

The two wrestled, and the teenager’s hands — perhaps inadvertently — went near Rogero’s ankle-holstered gun under his pants leg. The agent shook off the youth, reached down, pulled out his gun, pointed it at the teenager and ordered him to the pavement.

From there, as the police arrived, the altercation slowly calmed down.