Sources say at least two detectives witnessed the attack on Alexian Lien and did not directly intervene. And investigators are still working to determine what role, if any, was played by the other three officers.
What is clear, sources say, is that the men did not begin to come forward until late Wednesday, four full-days after the incident.
And detectives are also investigating reports that several others in the group may have been off-duty New York City correction officers.
An undercover detective has informed Internal Affairs that he was present at the time of the confrontation.
The undercover narcotics detective, himself a motorcycle rider, was off duty. Official sources say he did not get involved because he did not want to blow his cover. Internal Affairs is now investigating. The undercover detective is being advised by an attorney.
Also Friday night, 38-year-old Reginald Chance of Brooklyn turned himself in to police and is in custody. Detectives believe he used his silver helmet to smash the driver's side window of the victim's SUV. However, his role in the actual assault of the driver is unclear.
Earlier Friday, the biker who allegedly opened the SUV's door at one point during the chase, is now in custody.
35-year-old Robert Sims, grabbed the SUV's door at 5:05 seconds into the YouTube video, surrendered to police in Brooklyn earlier Friday.
Detectives are also looking at about a half dozen other bikers who may have had a role in the assault of the driver. Some have already been interviewed by investigators after being identified by video and photographs that have been coming in. Investigators are interviewing as many motorcyclists as possible to determine their roles before filing charges.
"This is a complex investigation with a lot of people involved," a source said.
Dayana Mejia cried during a press conference in New York City. Mejia says her partner and a biker left paralyzed in the confrontation, 32-year-old Edwin Mieses Jr., is an adoring father to the couple's two children.
"I love him so much it tears me up that anyone could think that Edwin in any way deserves what happened to him," she said.
Mejia says the people who participated in the motorcycle ride are "not thugs."
Gloria Allred, Mieses' attorney, says he was trying to "calm people down" when the SUV hit him on Sunday.
Video shows the SUV surrounded by dozens of helmeted riders. The driver, Alexian Lien, drove through the crowd and struck Mieses.
Investigators have searched the home of another Brooklyn motorcyclist, believed to have been the one who tried to open the driver's side door of the SUV while it was on the Henry Hudson Parkway. No arrests were made.
Also, police want to speak with two bystanders about what happened, and they have released images of the witnesses.
Everything started when the Range Rover bumped a biker on the Henry Hudson Parkway. As motorcyclists gathered around Lien's vehicle, he took off, running over Edwin Mieses and sparking the chase and vicious assault that followed.
Bikers insist that Lien was the aggressor.
"He drove erratically and bumped the bike on the side," one biker said. "When he bumped that bike on the side, that bike became aggressive because his life was in danger."
Meises' family, which is calling for charges against Lien, is expected to respond to a statement from Lien's wife.
Rosalyn Ng explained why her husband fled the scene and inadvertently drove over Mieses, saying their lives were put in grave danger.
"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," Ng said.
She said her family's sympathies went out to Mieses, who broke both legs and suffered spinal injuries that may leave him paralyzed, but said there was no other option than to flee.
"Our fear for our lives was confirmed when the incident ended with the ruthless and brutal attack on my husband, me, and, most importantly, our 2-year-old child," Ng said. "We know in our hearts that we could not have done anything differently, and we believe that anyone faced with this sort of grave danger would have taken the same course of action in order to protect their family."
The biker involved in the initial accident, Christopher Cruz, is charged with reckless driving and unlawful imprisonment. Prosecutors served notice that they intend to take the case against Cruz to a grand jury, a sign that more serious charges are likely.
A second suspect, Allen Edwards, 42, of Jamaica, Queens, surrendered to police at the 33rd Precinct Tuesday night. It is believed he is the man who punched the rear window of the SUV with his fists at the end of the video.
He was held and questioned overnight Tuesday, and police initially said he would be charged with reckless endangerment, criminal mischief and menacing. But the office declined to prosecute at this time, pending further investigation of the entire incident.
Anyone with information regarding the incident is asked to call Crime Stoppers at 1-800-577-TIPS (8477).