Colin Kaepernick has sparked outrage since his decision to not stand for the national anthem became public. The 49ers’ quarterback revealed Tuesday that his protest also has sparked death threats.

Kaepernick, who was heckled by some fans during the 49ers’ loss at Carolina on Sunday, said he hadn’t alerted team security to the threats, which have come from “a couple of different avenues.” A team spokesman said the 49ers investigate and evaluate any threats to their players, staff or facilities, and act accordingly.

“To me, if something like that were to happen, you’ve proved my point,” Kaepernick said. “And it will be loud and clear for everyone why it happened. And that would move this movement forward at a greater speed than what it is even now.

“Granted, I don’t want that to happen. But that’s the (reality) of what can happen. And I knew there were other things that came along with this when I first stood up and spoke about it. So it’s not something I haven’t thought about.”

Kaepernick has taken a stance to bring awareness to a variety of social issues, with police brutality and other forms of racial injustice being foremost among them.

On Tuesday, he spoke for about 12 minutes a day after the Tulsa (Okla.) Police Department released a dash-cam video showing Terence Crutcher, 40, an unarmed black man, being shot and killed by a female officer, who has been placed on paid leave since Cutcher’s death Friday.

Police have said Crutcher, who called for assistance because his vehicle was stalled, refused orders to put up his hands. Crutcher does not appear to be belligerent in the video. In it, four police officers decline to check on Crutcher before walking away less than a minute after he was shot.

The U.S. Justice Department and the Tulsa police have opened an investigation into the shooting.

“They shot and killed a man and walked around like it wasn’t a human being,” Kaepernick said. “People are being killed and not even being treated as human beings. No one went and checked on him. No one tried to resuscitate him. Nothing. They walked around, went about their business and made up lies to cover up the murder they just committed. That’s not right, and they should be in prison for that.”

Kaepernick has received support from around the league. In Week 2, at least 16 other NFL players either knelt or raised a fist during the national anthem, including five of Kaepernick’s teammates.

However, his stance also has inspired a backlash. On Sunday, some fans yelled at Kaepernick and raised a middle finger as he left the field at halftime.

“They either don’t care about what’s going on, or they don’t understand it,” Kaepernick said. “I find it very hard that people don’t understand what’s going on. I think the message has been out there loud and clear for quite some time now …

“There’s a lot of racism disguised as patriotism in this country. And people don’t like to address that. And they don’t like to address what the root of this protest is.”

Asked if he heard racial slurs Sunday, Kaepernick offered that he “heard a lot of different things,” but focused on the many fans who showed support.

At this point, only black players have joined in some form of protest during the anthem. However, New England defensive tackle Chris Long, who is white, recently said he won’t kneel for the anthem, but he is finding “a lot of truth” in what Kaepernick and other players are saying.

“Those aren’t mutually exclusive ideas,” said Long, who added: “I play in a league that's 70 percent black and my peers, guys I come to work with, guys I respect who are very socially aware and are intellectual guys, if they identify something that they think is worth putting their reputations on the line, creating controversy, I'm going to listen to those guys.”

Kaepernick said he has spoken briefly with Long and professional soccer player Megan Rapinoe, who has joined Kaepernick in kneeling for the anthem.

“That’s where it gets very touchy is a white player standing up for this is like, ‘OK, now we really have to address it. It isn’t just black people speaking out because they’re being attacked,’” Kaepernick said of Long’s comments. “No, it’s a real issue. And it’s disproportionately an issue to people of color. I think it was huge that Chris stood up and took that stand … I don’t know if he realizes how much that means to this movement and trying to get things changed.”

Kaepernick has said he will donate the proceeds he receives from his top-selling jersey to community organizations, along with the first $1 million he earns this season. On Tuesday, Kaepernick said he will donate $100,000 every month for the next 10 months to different organizations. A web site is being designed that will track where the money is being donated, and how those organizations are using the funds.

Eric Branch is a San Francisco Chronicle staff writer. Email: ebranch@sfchronicle.com Twitter: @Eric_Branch