The FBI has called Den Hollander the "primary subject," and he is dead, the statement reads.
Earlier, two law enforcement sources told CNN that the suspect died of what is believed to be a self-inflicted gunshot wound.
The judge's son, Daniel Anderl, a 20-year-old student at Catholic University, was killed in the shooting, and Mark Anderl, the judge's husband and a defense attorney, was injured, according to Freda Wolfson, US District Chief Judge in New Jersey. Salas was unharmed, Wolfson said.
Mark Anderl is in stable condition and "seems to be OK," said Carlos Salas, the judge's brother.
Both the US Marshals and FBI are investigating the shooting. Initial reports from law enforcement said Daniel Anderl, with his father standing right behind him, opened the door to the family home to a hail of gunfire, a law enforcement source told CNN. The gunman fled, the sources said.
A FedEx package addressed to Salas was found by officials investigating a vehicle associated with the suspect, according to a law enforcement source. The suspect's body was found in the town of Rockland in Sullivan County, New York, according to Trooper Steven Nevel of New York State Police.
The gunman appeared to be wearing a FedEx uniform, a law enforcement official with direct knowledge of the investigation told CNN.
"We are aware of the media reports and are fully cooperating with investigating authorities," Jonathan Lyons, a spokesman for FedEx, said in an email statement.
Law enforcement has not been aware of any threats against the judge, the source told CNN. Investigators don't yet know the motive.
A family of the law
Salas became New Jersey's first Latina US District Court judge in 2011 after she was nominated to the bench by President Barack Obama and confirmed by the Senate.
Federal court records show that she has presided over several high-profiles cases, including the financial fraud case of "Real Housewives of New Jersey" stars Teresa and Joe Giudice.
She also handled the 2018 sentencing of Farad Roland, who was found guilty of federal racketeering charges and sentenced to 45 years in prison by Salas. Roland was the leader of the South Side Cartel, "one of Newark's most violent street gangs," a news release from the US Justice Department said.
On Thursday, Salas was assigned to handle a class action lawsuit brought against Deutsche Bank by Ali Karimi on behalf of investors who purchased securities from the bank between November 7, 2017, and July 6, 2020. The complaint alleges that the bank "failed to properly monitor customers that the Bank itself deemed to be high risk, including, among others, the convicted sex offender Jeffrey Epstein," federal court records show.
In a 2018 profile in New Jersey Monthly, Salas said that she met Mark Anderl when he was an assistant prosecutor in the Essex County Prosecutor's Office and she was a second-year law school intern.
"I was literally getting fingerprinted" when he approached her, she told the mag