The city has closed a Brooklyn jail and relocated the people being held there as a part of the de Blasio administration's strategy to close the facilities on Rikers Island and replace them with four borough-based jails.

Most of the approximately 390 detainees at the Brooklyn Detention Complex on Atlantic Avenue were transferred to the Manhattan Detention Complex and the Vernon C. Bain Center, a jail located on a barge near the Bronx, City Hall spokesperson Avery Cohen confirmed. About 20 people were moved to Rikers Island, either because they required more security or are at least 50-years-old and needed units made for older detainees, according to Cohen. The House of Detention, as it's known, officially closed Thursday, the Brooklyn Paper first reported.

The Department of Correction personnel were all moved to other facilities as well, except for about 10 staffers who will maintain a bail window, preserve records and equipment, and provide site security.

Detainees at the jail suffered brutally hot temperatures during a heatwave last summer, spurring calls for funds for air-conditioning from the Board of Correction.

Brooklyn Councilmember Brad Lander said he was "relieved" by the jail's closure. With no air conditioning, detainees and personnel suffered hot temperatures in the poorly ventilated building, with "no meaningful plan to make it better," he said, recalling his tour of the facility last summer.

"Being there during the heatwave was horrific," Lander told Gothamist. "We shouldn't be keeping human beings in those conditions."

The House of Detention will eventually be torn down and rebuilt as a 295-foot jail as a part of Mayor Bill de Blasio's strategy to close all facilities on Rikers Island by 2026 and build four new jails in every borough except Staten Island.

The city's jail population is projected to drop to about 3,300 people by 2026, thanks in part to criminal justice reform legislation that passed last year, including a major reduction in the use of bash bail. The number of people held in city jails recently dipped to 6,000 from 7,700 in late 2018.

Once the building is demolished, a 295-foot jail will rise in place of the existing 170-foot building, which can hold 815 adults. The new facility will have about 886 beds, city documents show.

It is not clear when the detention complex will be torn down. The city will begin seeking construction proposals by the middle of 2021, and hopes to finish the new Brooklyn jail before 2026.

The transfer process in Brooklyn began in mid-November, when the de Blasio administration announced that the Brooklyn jail would close at the end of January, and that the Eric M. Taylor Center on Rikers would shut down in March.

"This is faster than the timeline that was agreed to when the plan to close Rikers was adopted and that's a good sign," Lander added, noting all the facilities are inadequate, but sees the Brooklyn site's closure as moving forward on the "ambitious plan" to close Rikers.

The $8.7-billion plan was approved by City Council in October after months of backlash to the plan from groups opposed to taller structures built in their neighborhoods to a group who want Rikers shuttered without building new facilities. Members of the group No New Jails have protested various hearings to urge the city to invest in communities with stable housing, restorative justice or reparations, rather than build any new jails at all. (No New Jails did not immediately respond to a request for comment.)

City officials have argued newer facilities will be designed more humanely and will help detainees be closer to the courts system and easier for loved ones to visit. DOC Commissioner Cynthia Brann said the new Brooklyn jail would "be built to reflect this city's commitment to a smaller, safer, and fairer correctional system."

"Its design will reflect our values and will support modern and humane practices, improving the experience for people in custody and their families, and providing a safer work environment for the public servants who perform one of the city's most challenging jobs," Brann said in a statement.

The Close Rikers campaign, which was not immediately available to comment Friday, has previously called on the city to be more transparent about the demolition and closure timelines. In a November statement, the campaign coordinator Brandon Holmes said it was "unsettling" that Correction staff would not be reduced, which remained the case at the House of Detention this week.