Newly released surveillance video shows the terrifying moments an armed robber boarded a Seattle bus and how passengers took him down.

The incident began Nov. 25 when a masked man got on the bus at a stop in downtown Seattle and, at first, sat down like a fellow passenger.

"We noticed that his face was kind of covered and he was wearing a hoodie, too, so you couldn't quite tell what was going on ," passenger Chris Briggs told local ABC affiliate KOMO.

The gunman, identified by Seattle police as 19-year-old Trevonnte Brown, then pulled out a handgun and demanded that two passengers hand him their cellphones.

"He came up to me … stuck the gun at me and took my phone," said Briggs, one of the two passengers robbed. "He jabbed me a little harder and said, 'Don't make this any harder than it has to be.'"

As Brown made his way to the front of the bus, a seated passenger lunged at him and his gun, even as Brown pointed it in the passenger's face, according to KOMO.

Other passengers, including Briggs, then jumped into the fray and pinned Brown down to the ground.

"People were kind of committed at that point," Briggs said. "It was just kinda one of those things that no one gave any thought to once things started happening."

Brown was arrested and charged with three counts of robbery and one count of attempted robbery, according to KOMO. He pleaded guilty to all counts, reports KOMO.

Brown is being held on $350,000 bail. The next hearing in his case is scheduled for Dec. 30.