South Tampa, Florida -- Tampa police say the third person arrested in the beating and robbery of Sgt. Johnny Aparicio is 18-year-old Jared Richardson.
In video released by police, Richardson can be seen crossing the front lawn of the house where surveillance images of the beating were recorded, say police.
Photo Gallery: Soldier beaten and robbed in South Tampa
They say it's Richardson who joins the other three suspects as they kick and punch Aparicio without mercy. And it was Richardson, say investigators, who was driving the Chevy Impala seen turning the corner just before Aparicio was attacked.
Lt. Mary O'Connor says the blinker light was a dead giveaway.
"If you look on the video, you can see the right front blinker, the right rear blinker is blinking rapidly. We've identified that as being the same vehicle and Mr. Richardson has stated as such."
Over the weekend, investigators also arrested 18-year-old Lerome Howard and 18-year-old Geroshe Lewis, charging each with aggravated battery and robbery.
Police say leads were generated by the video and by at least one of the suspects telling friend about the attack.
"We're really glad that they had it, because it shows that people are watching," said Martha, a neighbor of the man whose security system captured the video.
Hillsborough County school officials say Richardson attended Brandon High school, and that Lewis went to Robinson High, just blocks from where the attack occurred. They say both were seniors, and given the seriousness of the charges, neither will be allowed to return to class.
Brandi Cook, one of Lewis' classmates, says news of his arrest surprised her.
"I really didn't think that he would do that. It didn't seem like him," she said.
As for Sgt. Aparicio, who spoke briefly 10 News, he says he's recovering and trying to stay out of the spotlight.
Police say he has been informed of the arrests.
"He's appreciative," said Lt. O'Connor, "I think he'll feel much better once all four of them are in jail."
With three suspects now arrested, Tampa police say they expect it won't take long for them to identify and arrest the fourth attacker.