Lawrence G. Nassar, the doctor convicted of sexually abusing young female gymnasts, was stabbed multiple times in the chest, back and neck on Sunday at the federal prison in Florida where he is serving a 60-year sentence, according to three people with knowledge of the situation.
Mr. Nassar, 59, was in stable condition, conscious and responsive at a nearby hospital after he was attacked by another inmate at the Federal Correctional Complex Coleman, a sprawling prison compound in Central Florida, a senior law enforcement official said.
It is not clear when the altercation took place or what prompted the attack. A spokeswoman for the Federal Bureau of Prisons, which manages the complex, would not confirm that Mr. Nassar was involved but said an inmate had been assaulted around 2:35 p.m. on Sunday, was immediately given “lifesaving” measures and was rushed to a hospital by paramedics.
Mr. Nassar was “shanked” repeatedly and suffered a collapsed lung, according to Joe Rojas, the president of Local 506, which represents employees at the prison, citing the account of a union member who responded to the attack.
“The man is lucky to be alive,” said Mr. Rojas, who recently led a demonstration to protest understaffing at the complex of five maximum-, medium- and low-security facilities.
It is not the first time Mr. Nassar has been subjected to violence behind bars: He was assaulted in May 2018 shortly after being released into the general population of the federal penitentiary in Tucson, Ariz., his court-appointed lawyer reported at the time.
He was later moved into a more secure unit and eventually transferred to Coleman II, a penitentiary known for having a “safe” unit for high-risk targets, including sex offenders, gang members, former law enforcement officials or high-profile prisoners. He was in a general population unit, not in protective custody, at the time of the attack, an official with knowledge of the situation said.
Prison officials are investigating the attack and reviewing video surveillance footage.
The episode adds to the long, troubled case of a once-prominent sports physician accused of molesting and assaulting dozens of young women and children, including athletes at Michigan State University, Olympians and members of the U.S. national gymnastics team, all in the guise of providing treatment and examinations.
In a scathing 2021 report, the inspector general for the Justice Department found that the F.B.I. initially botched the investigation, allowing Mr. Nassar to assault more young women.
Mr. Nassar pleaded guilty to federal charges in 2017. He was sentenced to an additional 40 to 125 years by a judge in Michigan the next year, after pleading guilty to three additional counts of sexual assault. A federal judge ordered that sentence to run concurrently and remanded him to federal custody.
The incident is also the latest in a series of suicides and violent attacks on some of the most notorious inmates in the chronically understaffed Federal Bureau of Prisons. Last month, Theodore J. Kaczynski, the man known as the Unabomber who killed three people and injured 23 in a bombing rampage from 1978 to 1995, died by suicide at a federal prison medical center in North Carolina.
In 2018, James Bulger, a gangster from Boston known as Whitey, was beaten to death at a West Virginia federal prison after a cascade of management failures and breaches of protocol left him unattended and vulnerable to attack, the inspector general found. A similar environment of dysfunction was pervasive at the Manhattan federal prison where the financier Jeffrey Epstein hanged himself in 2019, the inspector general said in a report released last month.
Last year, 13 female athletes who were sexually assaulted by Mr. Nassar each sought $10 million from the F.B.I., claiming agents mishandled the investigation, allowing him to continue abusing more victims.
The athletes in the lawsuit were abused by Mr. Nassar when they were at the Twistars gymnastics club, outside Lansing, Mich. John Geddert, who owned Twistars and referred injured athletes to Mr. Nassar, fueling a cycle of abuse, killed himself in 2021 after he was charged with human trafficking.
Some of the athletes, who were middle school or high school students at the time, were assaulted after the F.B.I. was made aware of the abuse allegations in 2015, lawyers for the women said.
In 2021, the department’s inspector general sharply criticized the F.B.I.’s handling of the case, saying that Mr. Nassar had abused 70 or more young athletes from July 2015, when U.S.A. Gymnastics first reported allegations against him to the F.B.I.’s Indianapolis field office, to August 2016, when the Michigan State University Police Department received a separate complaint.