Updated

The Michigan State gunman had a note in his pocket "indicating a threat" to two New Jersey schools when he killed himself following a deadly shooting spree at the university, police said.

Anthony McRae, 43, killed three MSU students and critically wounded five others when he opened fire on the East Lansing campus at 8:30 p.m. Monday, which sparked a tense and chaotic manhunt that ended about four hours later when police found McRae with a self-inflicted gunshot wound. 

Officers found a note in his pocket about a threat to two public schools in Ewing, New Jersey, which were closed Tuesday and guarded by a heavy police presence "out of an abundance of caution," according to a statement by the Ewing Police Department. 

MSU SHOOTER WHO KILLED 3 STUDENTS, INJURED 5 IDENTIFIED AS ANTHONY MCRAE: LIVE UPDATES

MSU gunman Anthony McRae seen on surveillance footage

The suspect, Anthony McRae, in a deadly shooting spree at Michigan State University in East Lansing Monday night died of an apparent self-inflicted gunshot wound, authorities said. (MSU Police & Public Safety/LOCAL NEWS X /TMX)

Details about what was written on the note weren't released, but police said there's no threat to the New Jersey communities. 

McRae has ties to Ewing Township, but hasn't lived in the area for several years, police said.

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MSU gunman Anthony McRae wears jacket in mugshot

Michigan State shooter who killed 3 students, injured 5 identified as Anthony McRae. (Michigan Department of Corrections)

Investigators indicated McRae has a history of mental illness, and officers told 911 dispatchers that they were called for a welfare check for him last week. 

Lansing police declined to provide details about the welfare check, telling Fox News Digital in an email, "His history is part of the investigation, so we cannot comment at this time."

MSU shooting

First responders stage outside Berkey Hall on the campus of Michigan State University, late Monday, Feb. 13, 2023, in East Lansing, Mich. (AP Photo/Al Goldis) (AP Photo/Al Goldis)

McRae was on probation for 18 months until May 2021 for possessing a loaded, concealed gun without a permit, according to Michigan's Corrections Department.

Police confronted McRae about five miles from campus in an industrial area, where he killed himself, investigators said. 

MICHIGAN STATE UNIVERSITY SHOOTER ANTHONY MCRAE FOUND DEAD AFTER CALLER'S TIP TO POLICE, OFFICIALS SAY

Law enforcement said they don't know at this point what the motive was. 

The names of the three students who died haven't been released as of Tuesday afternoon.

Emergency personnel respond to a shooting at Michigan State University in East Lansing, Michigan, U.S., February 13, 2023.   REUTERS/Dieu-Nalio Chery

Emergency personnel respond to a shooting at Michigan State University in East Lansing, Michigan, U.S., February 13, 2023.   REUTERS/Dieu-Nalio Chery

Four of the five students who were wounded needed surgery, and they are all in critical condition, Dr. Denny Martin, the acting president and chief medical officer for E.W. Sparrow Hospital in Lansing, said during Tuesday morning's press conference. 

"This is something we talked about this morning that we practice for very often but never want to have to do, and we did it amazing as well," said Martin, who was visibly emotional and struggled to choke back tears. "We can't forget we had general surgeons and cardiothoracic surgeons, neurosurgeons who didn't get a lot of sleep last night. 

"So many people that just came in, we received a lot of texts that were just, you know, ‘I’m on my way,' just with people showing up where they needed to be. It was a sad but very proud night for all of us here." 

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Hundreds of officers from the FBI, ATF, Michigan State Police and other law enforcement agencies assisted local officials in securing the campus. 

The FAA implemented temporary flight restrictions over the university's campus through Wednesday.