Robert Sims, 35, surrendered to NYPD in Brooklyn on Friday. Authorities believe he was the one who grabbed the SUV's door during the videotaped road-rage incident. Charges are pending.
Another biker, who is seen on video smashing the window of the SUV with his helmet, also turned himself in. Reginald Chance, 38, of Brooklyn, surrendered late Friday. His role in the alleged assault beyond the window smashing is not immediately clear.
The incident happened Sunday. In a clip posted on YouTube, a group of about 20 to 30 helmeted motorcyclists are seen gathered around a black Range Roger SUV. One biker suddenly slowed down in front of the SUV and the two bumped.
The motorcyclists came to a halt. Police say some of them started damaging the SUV. The 33-year-old SUV driver, Alexian Lien, accelerated to escape, running over 32-year-old Edwin Mieses Jr.
Dayana Mejia, Mieses' longtime girlfriend, cried as she described her longtime partner as an adoring father to the couple's two children.
"He is the best father I know," she said during the Friday press conference. "And he would give the shirt off his back to anyone."
Mieses' defense attorney, Gloria Allred, said her client suffered a broken spine, fractured ribs, a punctured lung and a torn aortic valve. Allred claims Mieses was attempting to diffuse the situation.
"He told everyone to move one and go back to riding, and he turned his back to the SUV to start walking back to his own bike," Allred said.
Both of Mieses' legs were broken, and he suffered spinal injuries that may leave him paralyzed. Lien's wife, Rosalyn Ng, has said that her family's sympathies go out to Mieses, but that they had to flee a dangerous situation. She said her husband was trying to protect her and their 2-year-old child, who was also in the car at the time.
"We were faced with a life-threatening situation, and my husband was forced under the circumstances to take the actions that he did in order to protect the lives of our entire family," she said in a statement released on Thursday.
Mejia said the whole situation has been made worse by what she described as a "perception" that some people have about the riders who participated in the Sunday rally.
"They are not gang members. They are not thugs," Mejia said. "They are FedEx drivers, plumbers, military reservists, musicians. They are fathers and brothers and sons, and sisters and mothers."
She also said Mieses didn't know any of the people he was riding with on Sunday aside from one friend who traveled to New York with him. Mejia was referred to in earlier media reports as Mieses' wife, but she called him her partner on Friday.
Allred refused to comment on the fact that Mieses, who is from Lawrence, Mass., hasn't had a valid driver's license or permit in the state of Massachusetts since 1999. She said it was irrelevant to the case because he wasn't on his motorcycle when he was run over by the SUV.
Mieses was recently arrested in Andover, Mass., for driving with a revoked license. He also never applied for a motorcycle license.
According to police records, Mieses in June was named a habitual offender and his right to drive in the state was revoked until 2017. It wasn't clear if he had been licensed in any other state.
The Manhattan District Attorney's Office has charged one rider, 28-year-old Christopher Cruz, of Passaic, N.J., with unlawful imprisonment and reckless driving while authorities continue to search for other cyclists. According to ABC News, police have identified a prime suspect, who was seen in the video smashing the SUV's window with his helmet.
Investigators and prosecutors are tracking down and talking to dozens of helmet-clad motorcyclists seen in the video.
Meantime, ABC News' New York affiliate, WABC-TV, reports that an off-duty undercover detective was present at the time of the confrontation. The detective, himself a motorcycle rider, informed internal affairs, which is now investigating. Sources tell WABC-TV that the narcotics detective did not get involved in the situation because he did not want to blow his cover.
ABC News, WABC-TV and the Associated Press contributed to this report.