Detainees at Rikers Island spent an average of 115 days locked up at the jail last year – four times the national average, according to a federal monitor report published on Monday.

The report found the average length of stay for detainees at Rikers has nearly doubled from 61 days in 2016, when a federal court installed a monitor to oversee reforms at the troubled jail.

Nearly a quarter of the jail population was held for longer than a year in 2022, the report shows. The vast majority of those incarcerated at Rikers are awaiting trial, the report stated. As of Monday, 86% of people in custody across the city’s jails are waiting for their cases to conclude, according to data from the Vera Institute.

“There is no question that any personal challenges an individual may have faced prior to incarceration are only exacerbated by exposure to a correctional environment,” the report stated. “Reducing the overall jail population is necessary to support the overall reform efforts … because it would reduce the number of people exposed to the dangerous conditions.”

The Department of Correction did not immediately reply to a request for comment.

The report was published days after the resignation of Manuel Hernandez, the department’s top internal investigator.

Under Hernandez’s leadership, there was a “disturbing trend” of internal investigators being pressured to take a lenient approach while evaluating the use of excessive force, the report found. The monitor wrote that the Investigation Division’s “conclusions did not appear to be objective.”

“Misconduct was being identified much less frequently than in the past,” the report said. “Staff had been influenced or prompted, either overtly or implicitly, to adopt a more lenient approach when assessing cases and to change their practice in ways that compromised the quality of the investigations.”

Hernandez — a retired NYPD lieutenant — was appointed to the role last May by Correction Commissioner Louis Molina.

The report cited Hernandez’s departure from the post as “progress towards achieving compliance” and mitigating “any further decline in the quality of investigations.” A new deputy commissioner of the Investigation Division has not yet been appointed.

This story has been updated.