A former Prince George’s County jail guard was arrested Thursday on charges that he ignored a dying inmate accused of killing a police officer, walking away from the man’s cell and failing to seek help.

The federal civil rights charges against Anthony McIntosh, 48, come more than three years after 19-year-old Ronnie White was found strangled in the Prince George’s County jail. White’s death was ruled a homicide by the medical examiner, but a state police investigation later concluded that White could have killed himself.

McIntosh, who has said he found White hanging from a bedsheet, is not accused of attacking the inmate. Prosecutors allege that he spotted White, unresponsive and in apparent need of medical care, and left without helping or informing others. They allege that McIntosh tried to cover up the incident by lying in a report and that he also lied to a detective investigating the case.

The indictment — the first in the high-profile case — does not shed light on how White died June 29, 2008. White’s mother claimed in a lawsuit, which is pending, that her son was killed by guards. A state grand jury in 2008 declined to return an indictment. The next year, Glenn F. Ivey, then the county’s state’s attorney, said he did not have enough evidence to pursue charges.

McIntosh was arrested Thursday in New York, and authorities said he is scheduled to appear Friday in a New York courtroom. It was unclear whether he had retained an attorney.

Ronnie White (Prince George's County Department of Corrections)

McIntosh was for a long time the primary focus of the investigation into White’s death because he had access to White’s cell. Less than 48 hours earlier, White had been accused of killing Cpl. Richard S. Findley, who was run over by a truck.

In a 2009 interview with The Washington Post, McIntosh said he did not know Findley. He said he had not heard of the case until he arrived to work that day, and even then, it was in a mundane conversation with a sergeant.

McIntosh said in that interview that he panicked when he found White in his cell without a pulse, and he left without telling his supervisors that the inmate was dead. Law enforcement sources have said that McIntosh told investigators he did so because he had been in trouble for an earlier incident and worried about being involved in another disciplinary procedure.

During the investigation, McIntosh volunteered to a union leader that he found White hanging by a bedsheet about 10:15 a.m., 15 minutes before another guard found the inmate unresponsive on the floor. In meetings with investigators, the jail guard contradicted himself and could not remember details of how he had found the inmate. He also failed a polygraph when asked: “Did you put something around Ronnie White’s neck?” The medical examiner ruled White’s death a homicide and said he died of asphyxiation .

But a polygraph also determined that White was being truthful when he told investigators that he did not intentionally injure White, and another inmate said White seemed melancholy on the day he died. Detectives concluded that it was possible White had killed himself.

After an extensive investigation, Ivey said he would probably not be able to bring charges in connection with the death. At the time, he acknowledged that federal authorities were still investigating the case. He declined to comment Thursday.

The five-page federal indictment, filed in U.S. District Court in Greenbelt, charges McIntosh with depriving White of his due- process rights by demonstrating “deliberate indifference to his serious medical needs.” The indictment alleges that McIntosh ignored White when he was “in apparent need of emergency medical care.” Then, in a report and interview with a detective, McIntosh led authorities to believe that another guard first told him that White was unresponsive in his cell, according to the indictment.

McIntosh was allowed to resign from the department after his 2009 interview with The Post.

Efforts to reach family members of McIntosh were unsuccessful. Clothilda Harvey, a lawyer who once represented him, said she was no longer doing so and, therefore, could not comment on the indictment.

Efforts to reach members of White’s family were unsuccessful. In 2009, the family filed the lawsuit against Prince George’s County, McIntosh and two other guards who were assigned to the cell block where White died. Investigators concluded that one of those guards was on a meal break when White was fatally injured, and the other never left his spot in the jail control room, law enforcement sources have said. The suit, which seeks more than $153 million in damages, is ongoing, online court records show.

Staff researcher Jennifer Jenkins and staff writers Clarence Williams, Ovetta Wiggins and Aaron Davis contributed to this report.