Four people detained at an immigration detention center in New Jersey have gone missing, according to two senior officials.

The detainees were being held at the Delaney Hall facility in Newark, where Immigration and Customs Enforcement (ICE) has been holding individuals who are facing possible deportation. The four people were unaccounted for Thursday night, and federal authorities were looking into whether they were still on the grounds of the facility, or had somehow escaped, senior officials said.

Chopper 4 was over the scene Thursday afternoon showing law enforcement and ICE agents canvassing the area.

The wife of one detainee told NBC New York she rushed over to Delaney Hall after she got a call from her husband about a lockdown in his pod and a protest about inhumane conditions at the detention center. The wife of that detainee said she was worried about her husband’s safety.

A search was ongoing.

Local and state authorities were notified of the missing detainees, and some additional resources were called in to assist with the situation, according to the senior officials.

Delaney Hall made headlines in May after protests broke out at the 1,000-bed, privately owned facility.

Democratic U.S. Rep. LaMonica McIver was charged in a criminal complaint with two assault charges stemming from a May 9 visit to the center. She was indicted on Tuesday; The indictment includes three counts of assaulting, resisting, impeding and interfering with federal officials.

By law, members of Congress are authorized to go into federal immigration facilities as part of their oversight powers, even without notice. Congress passed a 2019 appropriations bill that spelled out the authority.

McIver said in a statement that she had “serious concerns about the reports of abusive circumstances at the facility,” and that her office had reached out to ICE for answers.

At the same visit that resulted in McIver’s charges, Newark Mayor Ras Baraka was arrested on a trespassing charge, which was later dropped. Baraka later filed a lawsuit against acting U.S. Attorney for New Jersey Alina Habba over what he said was a malicious prosecution.

In a statement, Baraka expressed concern for what had transpired at Delaney Hall on Thursday, “ranging from withholding food and poor treatment, to uprising and escaped detainees.”

The mayor went on to say the situation “lacks sufficient oversight of every basic detail — including local zoning laws and fundamental constitutional rights. This is why city officials and our congressional delegation need to be allowed entry to observe and monitor, any why private prisons pose a very real problem to our state and its constitution…We must put an end to this chaos and not allow this operation to continue unchecked.”