A police officer arrested a man after watching him grope four women near the Rockefeller Center Christmas tree, according to court documents. View Full Caption DNAinfo/Heather Holland

NEW YORK CITY — Police Officer Joseph Pecora watched as a 44-year-old man groped a woman near the Rockefeller Center Christmas tree on a recent evening — but despite it being clear what the man was doing, he said he had to wait for the suspect to strike twice more before he could intervene.

"We need to observe it at least three times before making an arrest," Pecora, of the Midtown North precinct, later told DNAinfo New York, adding that he's been warned by prosecutors that groping cases don't succeed in court unless the suspect has targeted multiple victims.

So, instead of confronting the suspect, Atta Saad, the first time he was "pushing his groin up against a woman's buttocks and repeatedly rub[bing] against her" at about 6:45 p.m. Dec. 1, Pecora had to watch and wait until Saad rubbed against three other women before he could move in to make an arrest, according to court records.

A MINIMUM OF THREE

"I was told by the ADA [assistant district attorney] in the past, you have to observe it three times. We work in plainclothes. We didn't want to give away our identity before hitting that three mark," Pecora said.

When asked about Pecora's statement regarding a three-victim minimum, a spokeswoman for the Manhattan District Attorney's office said they had no such policy.

The NYPD would not respond about whether there is a minimum number of incidents required before an officer can intervene, saying in a written statement that "when an officer observes an instance of forcible touching, an arrest will be effected in a timely manner. However, the totality of the circumstances such as the safety of the victim, public and officer will be taken into account."

► Read more: NYPD Officers' 1989 Conviction Colors Approach to Busting Gropers Today

Between Nov. 27, 2015 and Dec. 1, 2016, DNAinfo New York obtained court records for five suspects arrested for gropings in which police officers testified that they watched suspects touch, grab or rub multiple victims — one suspect groped a total of five women — before making an arrest. The five suspects groped a total of 20 women, according to the criminal complaints.

In some cases, several of the victims were aware they were being groped, and in others, many of them didn't know, according to the documents.

While no one could point to a written policy regarding the practice of waiting before making an arrest, DNAinfo New York interviewed a half dozen police officers and law enforcement experts who said they had a similar understanding.

In a case near Rockefeller Center on Dec. 1, NYPD Officer Scott Gomez watched as Raul Enriquez-Rodriguez groped five women at the southwest corner of Fifth Avenue and West 49th Street, rubbing "the back of his hand in a side to side motion on the women's buttocks," according to prosecutors.

Gomez didn't arrest Enriquez-Rodriguez until he saw him holding a cellphone up a sixth victim's skirt, court records show. It's not clear how much time passed between each incident.

'ONCE WE GET A COMPLAINANT, IT'S OVER'

Sgt. Christopher Roche, of NYPD’s Transit Division District 2 on Canal Street, is part of one of the 12 units citywide focusing on crimes within the subway system.

“If the woman being groped on — or however you want to call it — didn’t feel anything, we can’t do anything at that point.

"But once we get a complainant, it’s over,” Roche said.

Yet in the case of 56-year-old Demetrius Sherrod, who was charged with persistent sex abuse after groping three women in subway cars on Sept. 8, the officer who made the arrest, Detective Yeuris Majia, of the NYPD’s Transit division, did not make an arrest even after some of the women showed signs of being uncomfortable and told the officer so, the complaint shows.

In this instance, two of the women moved away from Sherrod after he touched them, and one told the officer his behavior was unwanted, according to a criminal complaint. Despite this, the officer waited to observe Sherrod strike again before making an arrest, according to a court records.

Majia had seen Sherrod touching the first woman’s butt with his hand, “alternating between his palm and his knuckles” while they were both riding an E train between 14th Street and Eighth Avenue and 42nd Street and Eighth Avenue at about 6:05 p.m., before she moved away from him, prosecutors said.

Majia did not respond to request for comment.

Anti-sexual harassment advocates say the practice of delayed intervention is troubling.

"For several people to have to go through that trauma for a perpetrator to be caught is unfair, and is also damaging to the victims," said Debjani Roy, deputy director of an advocacy group called iHollaBack, which has been collecting stories from victims of public harassment since it launched in 2005.

She added that the gray area of what is an unwanted sexual touch and what is an accidental brush is confusing enough for victims without police knowingly standing by and watching it happen to multiple women.

"A lot of perpetrators, they test out the limits," Roy said. "Maybe the first step is moving closer to the woman, next step might be to brush up to the woman, then it might be grabbing. From the victim's perspective, you kind of suspect something is happening, but it's not a clear act. You know when you start to feel uncomfortable."

PROVING SEXUAL INTENT

Those in law enforcement said the practice of waiting to witness multiple incidents might be unseemly, but it's necessary due to the challenging nature of proving sexual intent when strangers touch in a crowded place like the subway or a tourist hub.

“Anyone can accidentally brush up against, or trip forward to try to right themselves and use that as a ready defense. You could try to charge, but it would be almost impossible to prosecute,” said a former detective of the NYPD's Special Victims Unit — which focuses on sex crimes including assaults and rapes — who worked with the department for 25 years before retiring a few years ago.

“But if it happens in succession in one visit to the transit system, that’s indicative of sexual assault,” he said.

The former detective, who said he preferred not to be named, called the practice of waiting to witness multiple incidents a "course of conduct" or "terminology to prevent someone from saying it was an accident."

Richard D. Emery, a civil rights lawyer and former chairman of the Civilian Complaint Review Board (CCRB), also said the method was preferable to immediate arrest, adding it was a sign of “good training” by the NYPD.

"In terms of protecting the public, they're better off establishing a pattern," Emery said.

"You can't say it's allowable to have a cop let someone abuse a person, but it's better to watch that person abuse someone else and get a complainant, than it is to make the arrest and go by what the cop saw. That case will definitely be dropped. The cop’s between a rock and hard a place."

Lawyers for all defendants in this story did not respond to request for comment.

The number of forcible touching incidents citywide has fluctuated over the years, with 950 arrests in 2014, 1,043 in 2015, and 967 as of Dec. 7 of this year, according to the NYPD.

Three of the five suspects in the cases reviewed by DNAinfo were charged with misdemeanor forcible touching and/or sex abuse, which carries up to a year in jail. The charges and commensurate jail time do not increase even if there are multiple victims tied to an arrest, prosecutors said.

Two of the suspects had been convicted of sex abuse before, and had their charges elevated to persistent sex abuse, a felony — which carries more jail time under state law, according to their criminal complaints.

'THEY SHOULD GET THE GUY'

The practice came as a shock to victims, including Gabriella Geisinger, 27, who reported to police that she was groped during a rally outside of Trump Tower on Oct. 19.

The first officer she approached to make a complaint on that day walked away without taking her complaint, she said. She then went to a second officer who took down her statement.

“I feel like we’ve all been victims to this bystander effect. If someone sees something, they should say something. Maybe cops don’t fall into that, but maybe they do,” Geisinger said. “I was under the impression that it’s not the police’s job to build a case. They should get the guy. When they see something bad happening, they should stop it.”

“It’s like, ‘I saw him stealing a Twinkie, and I’m just going to make sure he’s a thief, so I’m gonna see him steal two more,'” she continued. "You might feel kind of ashamed that someone was taking advantage of you, but I think you should still know and be informed."

With contributed reporting from Maya Rajamani.