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