Delco sent a prisoner accused of jail assaults to a Philly lockup. Now his 59-year-old cellmate is dead.

Philadelphia prison officials had ample warning that Daquan Miller could pose a danger to those around him.

First, there was the 25-year-old’s volatile history in Delaware County’s George W. Hill Correctional Facility, where he allegedly assaulted two other prisoners last year using his handcuffs and fists — sending both men to the hospital, according to court records.

Then, on Jan. 27 — after Delaware County sent Miller to Philadelphia as part of a prisoner exchange — he was flagged as a behavioral health emergency, according to jail records and sources.

Hours later, he assured a social worker that he wasn’t homicidal, telling her, “I don’t understand why I’m an emergency,” and Miller was released back into what sources describe as a general-population unit. His cellmate, at Curran-Fromhold Correctional Facility in Northeast Philadelphia, was 59-year-old Mike Osborne.

The next morning, about 9 a.m. on Jan. 28, officers found Osborne unresponsive on the floor of the cell. The Philadelphia Medical Examiner would later determine that his death was homicide by blunt force trauma. When officers tried to remove Miller from the cell with Osborne, Miller immediately began fighting with other incarcerated men on the unit, according to an incident report.

The district attorney’s office is charging Miller with murder and reckless endangerment, a spokesperson said Wednesday.

Miller is already facing charges in four cases in Delaware County, including drug and gun charges, and three sets of charges for jail-based episodes. One involved a homemade weapon, a second resulted from Miller allegedly struggling with and spitting on a guard, and the third was the alleged assault on the two prisoners. Miller’s lawyer in Delaware County, Douglas Smith, declined to comment on the pending charges.

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A Philadelphia Department of Prisons spokesperson declined to answer questions about the case, including why the facility accepted the transfer of a man with charges related to jail-based violence — and why he was not placed in protective custody.

Prisons Commissioner Blanche Carney declined an interview request through a spokesperson, citing the ongoing investigation.

Corrections experts said the sequence of events represents a serious security lapse, and reflects ongoing safety issues at the jail, where there have been at least seven homicides since 2020. Before that, the jails had gone about five years without a homicide.

Anyone accepted through a prisoner exchange requires extra scrutiny, and careful placement, potentially in segregated custody, according to Ed Miranda, a retired deputy warden with the Philadelphia Department of Prisons.

“If he’s that high-profile, when you bring him down you should keep an eye on him because he’s trouble,” Miranda said. “He could turn your applecart upside down, which he did — and you got another body.”

» READ MORE: The escape of two men from a Philly jail went unnoticed because a guard was sleeping on the job

Miller’s court record and prison history show many signs of mental illness.

In the Philadelphia jails, he was referred for emergency behavioral health care at least four times since May 2023, documents obtained by The Inquirer show.

On three separate days that month, when Miller was in Philadelphia jail for a probation violation hearing, officers filling out emergency behavioral health questionnaires for him checked “yes” for 30 different crisis indicators, including hallucinations, “agitated or extreme anger,” paranoia, self-harm, “bizarre behavior,” and “current assaultive or homicidal ideas.”

Soon he was back in Delaware County to face his four criminal cases there. In late May, the judge overseeing two of those cases ordered an evaluation of Miller’s competency to stand trial. He was deemed competent, his lawyer said. Then, in December, the county was able to send him back to Philadelphia as part of an intercounty exchange.

Housing an older man with a younger one, with a history of violence, can prove dangerous, Miranda said. In 2021, another 60-year-old man was also fatally beaten in a Philadelphia jail by his 22-year-old cellmate.

In fact, earlier on the same day Osborne was beaten to death in his cell, a 70-year-old man who’d been locked in a cell with a 32-year-old was taken to the hospital following a fight, according to a jail incident report obtained by The Inquirer.

Claire Shubik-Richards, executive director of the Pennsylvania Prison Society, said none of this should have happened: “No facility should be transferring people into Philadelphia. Philadelphia is not a safe facility. Philadelphia should be transferring people out of this facility.”

Inadequate staffing levels, she said, are creating “an untenable, dangerous situation.”

» READ MORE: A man who was fatally beaten in a Philadelphia jail should not have been there in the first place

The Philadelphia jails — which house about 4,600 people, most of them awaiting trial — have been under review by a federal monitor for more than a year, as part of the settlement of a class-action lawsuit over unconstitutional conditions there. Because the jails had failed to meet most of the court’s benchmarks by the end of 2023, that monitoring has been extended into 2026.

“Exposure to extended periods of isolation, institutional violence, squalor, and neglect breach all standards for humane confinement,” the monitor’s most recent report, from October 2023, said.

It noted that 44% of correctional officer jobs were vacant. One consequence was that staff were not always available to take people to health-care appointments. It found that less than 70% of behavioral health referrals were completed in a timely manner.

The jails have also seen four escapes in the last year, including a man who was found dead after he fled custody. Investigators determined that the escape of two men, whose absence was not noticed for nearly 19 hours, was enabled by posts left unoccupied, and by an officer who took a nap rather than complete the required headcount.

Staff writer Vinny Vella contributed to this article.