A man who believed he had been under demonic attacks drove to an Oklahoma restaurant and indiscriminately fired at a crowd, injuring three people, authorities say.

Alexander C. Tilghman, 28, was shot and killed by two citizens minutes after he arrived Thursday evening at Louie's Grill & Bar, a lakeside restaurant in Oklahoma City, police spokesman Capt. Bo Mathews said. Tilghman stood at the restaurant's entrance with a handgun and fired from the door before two men shot him, putting an end to "a very dangerous situation," Mathews told reporters at a news conference Friday.

"You can say they're heroes, which is a very good thing to say. ... Heroes is a great terminology. I just say they were two people who stopped a very tragic situation from going any further," Mathews said.

The two citizens, Carlos Nazario, 35, and Bryan Wittle, 39, were not armed, but they rushed to the trunks of their vehicles to grab their handguns as Tilghman began shooting. The two men will probably not face any charges because they were protecting other people's lives, Mathews told reporters.

Three people, 39-year-old Natalie Giles and two girls, were shot but are in good condition, police said. A fourth person broke his arm amid the chaos.

The shooting appears to be a random act of violence, police said.

"It doesn't look like he knew anybody at the restaurant. He didn't work at the restaurant. ... This is an ongoing investigation. That could change," Mathews said.

The shooting happened amid what has become a national epidemic of high-profile shootings. Just a week earlier, a gunman killed 10 and wounded at least 10 others at a Texas high school. On Friday, a middle school student opened fire inside an Indiana classroom, wounding a classmate and a teacher, who swatted the gun out of his hand. A Washington Post analysis found that since 1999, shootings during school hours have killed at least 141 students, educators and other people, with another 284 injured.

The incident at the Oklahoma restaurant energized the National Rifle Association, which immediately seized on the moment Friday, saying the actions of the two men are "just another example of how the best way to stop a bad guy with a gun is a good guy with a gun."

The powerful lobbying group also criticized Oklahoma Gov. Mary Fallin, who had vetoed a permit-less carry bill despite pressure from gun-rights advocates in the gun-friendly state.

The bill, which Oklahoma's House and Senate overwhelmingly passed, would have allowed gun owners who are at least 21 years old and military service members or veterans who are at least 18 years old to carry firearms, concealed or unconcealed, without a permit. A dozen other states have constitutional carry laws.

In a statement announcing her veto on May 11, Fallin, a Republican, pointed to two aspects of the bill: It would have eliminated the requirement for firearms safety training and would have reduced the level of background checks.

Fallin said she supports the right to own and carry firearms, openly or concealed, but that the bill would not allow law enforcement to distinguish between those who have been trained and vetted to carry guns and those who have not.

Tilghman, the restaurant shooter, does not have an extensive history with police, whose last contact with him was in 2003. Mathews said he's not aware of any "mental health problems," though he added that "in an act like this, you would have to assume that he probably had a little bit of mental illness."

Several videos on social media show a pattern of troubling behavior. Seven months before the shooting, Tilghman posted a Facebook video saying "Satan has taken over" his television. In the 36-minute clip, Tilghman can be heard flipping through random channels, at one point saying the demonic episodes were "a lot worse" than before.

In another video shared by KOCO 5 News, Tilghman said that he's "been going through a lot of demonic attacks recently," and that he has not heard "from any real people."

In a 22-second video circulating on Twitter, Tilghman talked about "transsexual clones."

Fox affiliate KOKH reported that Tilghman had posted videos of himself in a local zoo, talking about a demon-possessed squirrel that he said had been following him. Weeks before the shooting, Tilghman recorded a video near Oklahoma City's Lake Hefner and claimed that Satan was making the sounds of driving cars louder.

A man who was not named but said he is Tilghman's brother told KOCO 5 News that the shooting would have been avoided had Tilghman received the help he needed.

"Nobody reached out to him, you know. He was crying for me. I was like the only one, and a few other people. This tragedy could've been avoided. Me and my whole family and even his friends all thought that he should be put into a behavioral unit," the man said, speaking to a reporter through a closed window of a home.

It's unclear whether Tilghman had access to mental health treatment.