Mentally ill Bradley Ballard was found naked and unresponsive on the floor of his cell after seven increasingly agitated days

After a mentally ill Bradley Ballard made a lewd gesture to a female guard at the Rikers Island jail in New York, he was locked in his cell alone for seven increasingly agitated days in which he was denied some of his medication, clogged his toilet so that it overflowed, stripped off his clothes and tied a rubber band tightly around his genitals.

During that period, guards passed Ballard's cell in the mental observation unit dozens of times, peering through the window in the steel door but never venturing inside – until it was too late.

The 39-year-old Ballard was eventually found naked and unresponsive on the floor, covered in feces, his genitals swollen and badly infected. He was rushed to a hospital but died hours later.

"He didn't have to leave this world like that. They could have put him in a mental hospital, got him some treatment," Ballard's mother, Beverly Ann Griffin, said from her Houston, Texas, home. "He was a caring young man."

Ballard's death last September, detailed in documents obtained by the Associated Press and in interviews with two city officials on condition of anonymity, came five months before another Rikers inmate in a similar mental health unit died in a cell that climbed to a suffocating 101F (38C) because of malfunctioning heating equipment.

Experts say Ballard's death is only the latest example of how poorly equipped the city's jail system is to handle the mentally ill, who make up about 40% of the 12,000 inmates in the nation's most populous city. A third of those inmates suffer from serious mental illnesses such as schizophrenia and bipolar disorder.

In Ballard's case, his family said he had been diagnosed as schizophrenic more than a decade ago, and he also had diabetes.

Faced with rising criticism over conditions at Rikers, Mayor Bill de Blasio has vowed reforms. Correction department spokesman Robin Campbell said in a statement Wednesday that Ballard's case is under investigation. He said mental health and jail officials have started shift-by-shift briefings on inmates like Ballard and are working on other measures "so that a similar tragedy will not happen again".

More tests are needed to determine exactly how Ballard died, the medical examiner's office says. But preliminary findings show that he probably succumbed to sepsis, an infection that has spread through the body, according to the two officials.

Ballard grew up in Houston and moved to New York to pursue a better life after working as a cook in a fried chicken restaurant, his family said. He spent six years behind bars after being arrested in 2004 for assaulting a receptionist and another employee of a New York law firm.

Last June, he was arrested in Houston on public lewdness and assault charges for punching and exposing himself to a bus driver. He was sent back to jail in New York for not telling his parole officer that he had left the city.

He was first placed in a Rikers facility for 17 days, then a correction department psychiatric hospital for 38 days. Then he was sent to a roughly 30-bed mental observation unit at Rikers.

In documents obtained by the AP via a public records request, Cathy Potler, executive director of the city board of correction, gave her account of Ballard's case, based on a review of records, security footage and interviews with inmates.

She noted that even though Ballard was in a unit where inmates are ordinarily allowed in and out of their cells to mingle with others for 14 hours a day, he was locked up continuously for seven days and for most of that time wasn't given his medication. The type of medication was not disclosed.

Guards confined Ballard to his cell on 4 September after he stared for hours at a female officer, rolled up his shirt to look like a penis and thrust it toward her, Potler said.

The next day, Potler wrote, Ballard intentionally flooded his combination sink-toilet, after which a mental health provider spoke with him for 15 seconds through the cell door. The next day, a plumber turned off the water to his cell.

Over the next few days, guards and deputy wardens looked in his cell dozens of times throughout the day, Potler wrote, and the inmate was at times seen at the door.

On 10 September video of an inmate delivering a tray of food to Ballard's cell showed the inmate covering his nose with his shirt and three officers backing away, "presumably because of the foul odor coming from the cell", Potler wrote.

Ballard was checked on at least two dozen times that day and night, with an officer at one point seen kicking his cell door several times, according to Potler's account.

By the time medical staffers were called in and his cell was opened, Ballard was so weak he couldn't move. He was pronounced dead early on the morning of 11 September.

Under city rules, mental health staffers are required to make twice-daily rounds in the unit where Ballard was jailed, and the guards on duty are supposed to be steadily assigned there and receive annual mental health training.

But mental health staffers visited Ballard's cell only once before he was discovered to be in distress, according to Potler. And of the 53 officers who worked in the unit in the days leading up to Ballard's death, only one was steady, and none had received the required annual refresher course on mental health, Potler wrote.

Following Ballard's death, department of health officials said a city investigation found workers missed multiple opportunities to treat him, transferred the unit chief to another facility and retrained staffers on how to do rounds and other procedures.

Jail officers have long complained that they aren't sufficiently trained to handle severely mentally ill inmates. At a recent public meeting, a union official said trainees get 21.5 hours of mental health training during their 16 weeks of academy instruction, plus the three-hour annual refresher.

In a statement, Norman Seabrook, president of the Correction Officers Benevolent Association, said Ballard's death was an example of "non-communication between medical staff and uniform staff". He said officers can notify members of the medical staff, "but it's clearly up to them and solely them to determine treatment".

Ballard's death, though tragic, was unsurprising to those familiar with how the mentally ill fare in jails, said Dr Bandy Lee, a Yale psychiatrist who was a co-author of a report critical of jail officials' use of solitary confinement.

"Correctional institutions are such a poor substitute for mental hospitals, which is what they're basically functioning as in our society," she said. "The problem is the correction setting is not fit to deliver the proper care, and in fact many of the settings exacerbate their symptoms."

Curtis Griffin, Ballard's stepfather, said a jail chaplain informed the family months ago of his son's death, but he wasn't told the specifics.

"They know," Griffin said, "that they were wrong in the way they handled the situation."