(CNN) An attorney who was found dead Monday is the suspect in a shooting at US District Judge Esther Salas' home, the US Attorney's Office in New Jersey said Monday afternoon.
Salas' son was killed and her husband injured in the Sunday attack at the family's home in North Brunswick, New Jersey.
The FBI identified Roy Den Hollander as the "primary subject," and said that he is dead, the US Attorney's office said in a statement. Den Hollander was a lawyer who once argued a case before Salas, according to court records.
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 out of his second surgery and in stable condition, according to his law partner, David Oakley, who added that Anderl will need another operation Tuesday.
In a lawsuit, Den Hollander represented a woman and her daughter who sought to register for the military's selective service, according to federal court records. Den Hollander's clients claimed the draft was unconstitutional because it barred women from registering.
Salas sided against a part of Den Hollander's arguments last spring, but also agreed with some of his claims and allowed the lawsuit to continue.
Den Hollander exited the case in June 2019, handing it over to a team of lawyers at the large New York-based law firm Boies Schiller Flexner.
Den Hollander said he "would not be able to see the case through" because he was terminally ill, Nick Gravante, a managing partner at the firm, told CNN.
On his website, Den Hollander describes himself as an "anti-feminist" lawyer who defends "men's rights."
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 multiple gunshots, a law enforcement source told CNN. The gunman fled, the source 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.
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 magazine. "We've been inseparable since 1992."
Mark Anderl works as a criminal defense attorney with Anderl & Oakley, PC, which specializes in state and federal criminal defense and juvenile and municipal court matters, according to their website.
Their son Daniel also might have had a future in law, Salas said in the New Jersey Monthly story.
"I don't want to dissuade him, but I was pulling for a doctor," she said in the 2018 story. "He's been arguing with us since he could talk -- practicing his advocacy skills."
Daniel was a rising junior at Catholic University in Washington, DC, and was enrolled for classes beginning in the next few weeks, the university said. He graduated cum laude from St. Joseph High School in 2018, said Jack Timko, director of external relations at the school.
"He was well-respected, well-liked by his peers and the faculty," Timko said. "He exemplified what we call a St. Joseph's man. Well prepared, well educated, respectful, professional."
North Brunswick Mayor Francis "Mac" Womack told CNN over the phone Sunday night that Mark Anderl is "one of the most straight-up honest attorneys" he has dealt with.
"He's a very, very exuberant, vibrant, one hundred percent pleasant person," Womack said. "He loves to talk about his wife, and he loves to brag about his son, and how his son would excel in baseball, and how he was doing down in college in Washington ... I'm just very sorry to see him going through this."
US Attorney General William Barr sent condolences for the Justice Department to the family.
"This kind of lawless, evil action carried out against a member of the federal judiciary will not be tolerated, and I have ordered the full resources of the FBI and the U.S. Marshals Service to investigate the matter," Barr said.
The FBI urged anyone with relevant information to call FBI Newark at 973-792-3001.
Correction: An earlier version of this article gave the wrong location for where the suspect's body was found.