CHICAGO (CBS) — A federal jury handed down a historic verdict Monday, convicting a veteran Chicago police officer for using unreasonable force and wounding two teenagers in an on-duty shooting caught on video in December 2013.

Marco Proano, 42, now faces significant prison time for firing 16 shots in nine seconds at a stolen Toyota Avalon full of teenagers at 95th and LaSalle, the Chicago Sun-Times is reporting. His sentencing has been set for Nov. 20, and prosecutors might move for his detention at a hearing next week. They described the shooting as “a gross abuse of the power he’s been given.”

It took jurors less than four hours to find Proano guilty of two civil rights violations. His trial began last week and included roughly two days of testimony. Proano did not take the stand, and he showed no obvious reaction to the jury’s verdict. He later shook hands with his lawyers and ultimately left the Dirksen Federal Courthouse without commenting.

“The vast majority of Chicago police officers do their job with vigilance and with respect for the constitutional rights of the citizens that they protect,” Acting U.S. Attorney Joel Levin said after the verdict was read. “In this situation, that’s not what Marco Proano did.”

Kevin Graham, president of Chicago’s Fraternal Order of Police, reacted with a statement that said, “the pressure on the police is making the job extremely difficult.”

“It seems that the criminal elements in our society are not accountable in our justice system, while the police face an intense scrutiny for every split second decision they make,” Graham said. “We will meet with our legal advisers to consider the next steps.”

Chicago Police Supt. Eddie Johnson said in his own statement that, “Mr. Proano’s actions are intolerable and stand in stark contrast to the hard work Chicago Police Officers do each day to build trust and serve our communities.” CPD has sought to fire Proano and his case is pending before the city’s police board, according to a department spokesman.

Proano is a married father of three born in Ecaudor who spent about a decade as a Chicago cop, working primarily in the Roseland neighborhood. His lawyer, Daniel Herbert, also represents Jason Van Dyke, the Chicago police officer facing murder charges in state court after fatally shooting 17-year-old Laquan McDonald on video.

Herbert also represented Aldo Brown, a Chicago police officer who was sentenced last year to two years in prison by a federal judge for using excessive force when he hit and kicked a convenience store clerk in September 2012. Brown was also caught on video.

The lawyers in Proano’s case spent more than two hours Monday giving their closing arguments. As the trial kicked off last week, Herbert told jurors that Proano’s sense of duty drew him to 95th and LaSalle on Dec. 22, 2013. There, two fellow officers had already crossed paths with the stolen Toyota packed with at least six teenagers.

By the time Proano arrived, the driver of the car had fled. A BB gun later fell out of the car, and Proano watched as the car suddenly began to reverse with one teen hanging out of a window. Another teen had lunged forward from the back seat, thrown the car into reverse and pushed the gas pedal with his hands. No one was in the vehicle’s path.

What happened next was caught on a police dashcam video. Jurors watched it repeatedly in real time and slow motion.

Proano can be seen in the video stepping forward, holding his gun sideways. Seconds later, he steps backward as the car reverses into view. Proano then lifts his gun again with both hands, upright, and a flash can be seen as he appears to open fire.

Proano has said he pulled the trigger to protect the teen hanging out the window. But prosecutors said Monday the officer “drew first, shot next” and “tried to justify later.”

One teen was wounded in his left hip and right heel. The other suffered a shoulder wound.

Herbert insisted the shooting lasted no more than four seconds, and he pointed to an Illinois law that appeared to justify Proano’s actions.

That law says police are justified in using deadly force when they reasonably believe it’s necessary to stop someone from escaping who “is attempting to escape by use of a deadly weapon.” Herbert said the car counts.

Prosecutors said deadly force was neither “reasonable” nor “necessary” under the circumstances. Rather, Assistant U.S. Attorney Erika Csicsila said Proano leapt out of his squad car that night “like a cowboy.”

And she said every shot he fired was unreasonable.

“The rules don’t change just because you’re on the South Side of Chicago,” Csicsila said.

(Source: Sun-Times Media Wire © Chicago Sun-Times 2016. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)

Watch & Listen LIVE