Updated

The Michigan State University gunman's dad said "only God knows" why Anthony McRae opened fired on the East Lansing campus Monday night, but he said Anthony hasn't been the same since his mother died nearly three years ago.

Anthony McRae, 43, didn't have any connections to MSU, police said, which makes the deadly attack more puzzling.

His dad, Michael McRae, told Fox News Digital that he "changed" after his mom died in September 2020.

Anthony stopped taking care of himself, quit his job, wouldn't look for work and spent all his time playing video games, he said. 

"He lived a sheltered world," Michael told Fox News Digital in a phone interview Tuesday afternoon. "He started changing. He was getting more and more bitter and angry. I'm asking him, ‘What’s on your mind?' But he wouldn't talk to me."

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MSU gunman Anthony McRae seen on surveillance footage

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

Michael said he tried to take him to church as a way to help, but Anthony "jumped in and out of the Bible."

"I told him the devil don't make you do nothing you don't want to," Michael said. "He was a good kid. He was a good worker. He just got out of control. I tried helping him."

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Anthony McRae fatally shot three MSU students and critically wounded five more around 8:30 p.m. Monday, according to police, which sparked a tense, hours-long manhunt while students ran and hid anywhere they could.

About four hours after gunshots first rang out, a tip from the public led police to McRae, who turned the gun on himself and died of a self-inflicted gunshot wound, police said.

MSU gunman Anthony McRae wears jacket in mugshot

The Michigan State shooter who killed three students and injured five has been identified as Anthony McRae. (Michigan Department of Corrections)

"I didn't know what happened. My neighbor told me he heard the news saying Anthony killed people and shot others, but I couldn't believe it," Michael said. "I don't want to believe he did this. I don't know what would make him think of doing this. … He's not the kind of guy who [would] do this."

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

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

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."

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.

Students on campus at Michigan State University after shooting

Students gather on the campus of Michigan State University after a shelter-in-place order was lifted early Tuesday, Feb. 14, in East Lansing, Michigan. (AP / Al Goldis)

The names of the three students who died had not been released as of Tuesday afternoon.

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. 

MSU shooting

First responders are seen on the Michigan State University campus, late Monday night, Feb. 13, 2023, in East Lansing, Michigan. (AP Photo / Al Goldis)

"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 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.

This story has been updated to reflect that Michael McRae is Anthony McRae’s father.