Four migrant men charged with felonies in an attack on two New York City Police Department officers Saturday outside a migrant shelter are en route to a California town near Mexico after they were released from custody and given bus tickets by a faith-based charity, a senior law enforcement official said.

The four men were among at least seven people arrested in the incident. They were staying in a New York City shelter, used false names with the charity, the source told CNN. It was not immediately clear who the four are among the group arrested this week in connection with the weekend incident.

Investigators say even though the defendants allegedly used false names with the charity and could be going to Mexico by way of Calexico, California, “we have no legal authority to chase them or attempt to stop them” because the Manhattan district attorney did not request bail and the defendants were released on their own recognizance, the law enforcement source said.

“We have to assume they intend to return to court, which, given the circumstances around their departure, seems unlikely,” the source added.

US Immigration and Customs Enforcement declined to comment.

The case follows a surge in migrants arriving at the US-Mexico border and, as a knock-on effect, in far-off major US cities – where many have gone on their own or on buses hired by Texas. Some 67,000 migrants are under New York City’s care, among more than 173,900 who’ve arrived in the city since spring 2022, a City Hall spokesperson told CNN on Thursday.

“The overwhelming number of immigrants, migrants, asylum-seekers, they want to be here and do what’s right. Those violent ones, we need to immediately have them removed from our city,” New York City Mayor Eric Adams told La Mega 97.9 FM on Thursday.

The attack outside the shelter “was disgusting, and they should be held accountable,” the Democrat added, saying he thinks they should not have been released from custody while noting the city does not have the authority to deport people.

Authorities Saturday arrested Yorman Reveron, 24, Kelvin Servita Arocha, 19, Darwin Andres Gomez-Izquiel, 19, and Wilson Juarez, 21, each charged with second-degree assault and second-degree obstructing governmental administration, according to a criminal complaint. Jhoan Boada, 22, was arrested Monday and charged with the same two counts, a complaint states.

Yohenry Brito, 24, was arrested Wednesday and arraigned Thursday on two counts of second-degree assault and one count of second-degree obstructing governmental administration, the Manhattan district attorney’s office told CNN. He also faces robbery and felony assault charges, the district attorney said. A 21-year-old arrested Wednesday on suspicion of robbery and felony assault was released and not charged, it said.

CNN has reached out to attorneys for all those named.

Brito is being held on bail, while the five others were released without bail, according to the district attorney, as police continue to investigate the attack. An assistant district attorney requested $15,000 bail or $50,000 bond for Brito, citing his alleged past interactions with law enforcement.

For those released without bail, the district attorney consented “to defendant release to allow us time to conduct a thorough analysis of the incident and defendant’s role in it,” according to a bail application for Boada that states the others were released without bail under similar requests.

A Manhattan Criminal Court judge ordered them to be “released on their own recognizance,” meaning they were released from custody without paying bail and told to return to court while the case is pending.

“Violence against police officers is never acceptable,” a spokesperson for Manhattan District Attorney Alvin Bragg told CNN. “Every defendant charged so far is facing felony charges that carry a penalty of up to seven years.”

Police, meanwhile, are trying to identify four more men who allegedly participated in the assault outside the migrant shelter, the law enforcement source said.

“Get them all and send them back,” New York Gov. Kathy Hochul, a Democrat, said of that effort. “You don’t touch our police officers. You don’t touch anyone.”

Arrested, charged and released without bail

The case calls to mind the controversial 2020 state bail reform act that essentially barred judges from setting bail in a sweeping number of crimes – a change critics say puts communities in danger.

Bragg in 2022 went further, issuing guidance to his assistants to refrain from asking for bail even in some cases that were still “bail eligible.”

“There is a presumption of pre-trial non-incarceration for every case except those with charges of homicide or the death of a victim” or charges involving weapons and serious physical injury, Bragg wrote in a January 2022 memo.

The defendants in the weekend assault outside the migrant shelter were charged with felonies for which prosecutors could have asked for bail, in particular because they were living in temporary shelters for migrants and had no “ties to the community” to ensure their return to court.

Prosecutors, however, did not ask for bail.

On Friday, Bragg defended his office’s decision to release five suspects.

“While the video is shocking and disturbing, in order to secure convictions in a court of law it is essential that we conclusively identify each defendant and specify each person’s participance in the incident,” Bragg said.

The five men who were released without bail are expected back in court in February and March. If they miss those court dates, arrest warrants likely would be issued for them.

Under New York’s 2014 sanctuary bill, a move to deport someone could follow their conviction on a felony charge.

How police say the incident unfolded

The incident unfolded as officers tried to break up a “disorderly group” outside the shelter near Times Square and a physical altercation ensued, police said.

When the officers tried to take a person into custody, “multiple unidentified individuals repeatedly kicked and punched the officers in the head and body” and later fled on foot, police said. The officers had minor injuries and were treated on the scene, police said.

While Brito was being apprehended, a struggle ensued with the officers, leading them to fall to the ground, according to a criminal complaint. Others then are accused of striking and kicking the officers, while Brito is accused of fleeing.

“It’s the police’s job to arrest them, the other criminal justice aspect makes the determination if they are going to be kept inside,” Adams told La Mega. “We did our job; we need to make sure that judges look over the seriousness of the case. I don’t believe they should have been released.”

“We cannot allow people to abuse our symbol of authority,” he said. “The police uniform is not only the individual, it is the symbol of authority and law and order and this is not a city of disorder. We’re going to be a city of order.”

The investigation continues and anyone with information is urged to come forward, a spokesperson for Bragg told CNN. “It is paramount that we conclusively identify each defendant and specify each participant’s role in the incident,” the spokesperson said.

CNN’s Nic F. Anderson and Samantha Beech contributed to this report.