At least 10 people were killed Friday after a gunman opened fire at Santa Fe High School in Santa Fe, Texas.

The victims are mostly students, The Associated Press reported.

The incident comes just six months after 26 people were killed when Devin Kelley opened fire at the First Baptist Church of Sutherland Springs in November.

In light of recent attacks, here’s what you need to know about Texas gun laws.     

Texas gun law 101

Gun critics argue that Texas gun laws are relatively lax. But Justin Sparks, a Firearms Program Attorney through the Texas Law Shield, a legal defense fund, told Fox News that “Texas is probably the middle of the pack,” adding that “there’s not a lot of prohibiting, but there is a lot of supervising.”  

“Generally speaking, in Texas, as long as you’re of age [18] and can pass the background check, you can buy a gun,” Sparks told Fox News.

However, a person must be 21-years-old before they can buy a handgun, he said.

Sparks added that there’s no special license to purchase a gun in Texas. According to the lobbying arm of the National Rifle Association, “a Texas resident, if not otherwise precluded by law, may purchase rifles and shotguns, ammunition, reloading components, or firearms accessories in contiguous states.”

There’s also no license to carry a gun once it’s purchased, he said. However, a permit is required to carry a handgun. And thanks to a bill that was passed in the Texas Legislature in 2015, handgun permit holders can now carry their handguns openly, Sparks said.

Overall, gun owners can keep the firearm in their home, vehicle or place of employment if their place of employment allows firearms in the building. In order to take it outside of those areas, however, a license is required, Sparks said.  

Problems typically arise when “someone goes and buys a firearm and doesn’t educate themselves on where they can carry it, or leaves it out in the open in their car,” he said.

Who cannot buy a gun in Texas?

Texas adheres to federal law when it comes to who can and cannot buy a gun, Sparks said.

If a person has been convicted of a felony, they cannot buy a gun. Firearm distributors who have a Federal Firearm License, or a FLL, can easily find out if someone has been convicted of a felony by running a background check, Sparks said.

Additionally, if a person is under indictment for an “offense that can land you in jail for more than a year,” Sparks said, you cannot have a firearm in Texas.

But five years after a convicted felon completes his or her sentence, they can own a gun again -- if they keep it in their home. However, Sparks acknowledged that this Texas law conflicts with federal law-- meaning that if it’s reported, it could result in that person’s arrest.

Additionally, those who are deemed “mentally unfit” by the state are prohibited from owning a gun -- an issue that Sparks said is “evolving” within the Texas legislature.

“I wouldn’t be surprised if the state eventually passes something that requires a disclosure of all mental health records-- even if they [the gun purchaser] were at a private mental health facility,” he said.

Given his background, how did Devin Kelley get a gun?

Devin Kelley previously served in the U.S. Air Force, but was discharged in 2014, an Air Force spokesperson confirmed to Fox News.

He was court-martialed in 2012 for assaulting his wife and child. He was then sentenced to 12 months in custody before being given a bad conduct discharge.

A 1968 Gun Control Act made it unlawful for a licensed firearms dealer to sell a weapon to any person who is given a dishonorable discharge. But because Kelley was discharged on bad conduct, the law was not triggered, Adam Winkler, a professor of law and a specialist in American constitutional law at the University of California at Los Angeles, told Fox News.

Kelley purchased two firearms from two separate Academy Sports + Outdoors stores in San Antonio in 2016 and 2017, respectively, the sporting goods store confirmed to Fox News in a statement on Monday. One of the purchases was allegedly a Ruger model AR-556 rifle.

“We also confirmed that both sales were approved by the National Instant Criminal Background Check System (NICS). We are cooperating with law enforcement as they investigate further,” the statement reads.

However, Kelley’s domestic violence charges should’ve been enough to prevent him from purchasing a gun, Winkler said -- but the Air Force most likely didn’t report this information to the federal background check system, thus allowing the purchase to go forward. 

“The underlying crime [domestic violence] in and of itself should’ve been enough,” Winkler said. “But for some reason, the military hasn’t been reporting bad conduct discharges.”

And Winkler’s prediction was right: The Air Force announced the Holloman Air Force Base Office of Special Investigations -- the base where Kelley was stationed -- failed to report Kelley’s domestic violence conviction to the FBI’s Criminal Justice Investigation Services Division for inclusion in the National Criminal Information Center database. The database is used to conduct background checks on those who want to purchase a gun.

If the Air Force had reported the conviction, the purchase would’ve been prevented because of the  Lautenberg Amendment, which enacted by Congress in 1996. The federal law prohibits people convicted of domestic violence from buying or possessing a gun.  

In response, the Heather Wilson, the secretary for the Air Force, told “Fox and Friends” that the Air Force is launching a “complete and full-scale review of this case and all others like it” to ensure something similar doesn’t happen in the future.

“If we find a problem, we’ll fix it,” she added.

The gunman was also denied a Texas handgun permit, Texas Gov. Greg Abbott told “Fox & Friends.”

"He was rejected either because he did not fully answer all the questions that are required to get a Texas gun permit, or he answered those questions wrong, that we still don't know," Abbott said.

The “biggest mystery,” Winkler said, is how Kelley was denied a handgun permit but was allowed to purchase a gun from the sporting goods store. But this information is currently unclear.

Additionally, Texas authorities confirmed Kelley did not have a license to carry. However, he did have a private security license -- often used by armed and unarmed security guards, personal protection officers, private investigators, and more, according to the Texas Department of Public Safety.

A criminal background check is typically required before someone can receive a private security license. 

The Boulder City Council unanimously passed a sweeping gun control ordinance Tuesday night banning "assault weapons" and bump stocks, even as a pro-Second Amendment group threatened to retaliate by suing individual councilmembers.

In a surprising turn, one Colorado councilwoman admitted that she disagreed with the ordinance "in many ways," saying it would invite a flood of litigation -- despite voting for it.

The city defines assault weapons as "semi-automatic firearms designed with military features to allow rapid spray firing for the quick and efficient killing of humans."

Included in the definition are "all semiautomatic action rifles with a detachable magazine with a capacity of twenty-one or more rounds," as well as "semiautomatic shotguns with a folding stock or a magazine capacity of more than six rounds or both."

"We're going to see a lot of court cases coming before us."

- Boulder City Councilwoman Mirabai Nagel

Those possessing assault weapons already can keep them under the law, but owning bump stocks and high-capacity magazines will be become illegal in July. Certain law enforcement and military personnel are exempted from the ordinance.

During the public comment period for the legislation, the nonprofit Mountain States Legal Foundation promised to sue the city for "violations of the Second, Fifth, and Fourteenth Amendments," as well as the Colorado Constitution, Fox's KDVR-TV reported.

RETIRED SUPREME COURT JUSTICE SAYS SECOND AMENDMENT SHOULD BE REPEALED 

A staff attorney for the group, Cody Wisniewski, said that individual councilmembers would be named in the lawsuit, according to the network.

Lawsuits generally cannot be directed personally at individual lawmakers for their official actions in legislative sessions, but naming elected officials in civil actions against the government is often acceptable as long as plaintiffs are not seeking to hold lawmakers personally liable for allegedly unconstitutional conduct.

The nonprofit's threat of legal action apparently did not come as a surprise to members of the city council, who said they anticipated complications.

"We're going to see a lot of court cases coming before us," Councilwoman Mirabai Nagle said despite voting for the ordinance, according to Colorado Public Radio. "I think that we're going to spend a lot of time and money. It's not that lives aren't worth that, but I think that there was a better way of going about this.

"I don't agree with this ordinance in many ways," Nagle added. "It's not perfect."

The proposed ordinance led to protests last week, with some pro-Second Amendment activists carrying long guns openly in the streets, according to local reports.

The Boulder City Council tweeted Tuesday that it would soon consider additional amendments to the ordinance, such as raising the age to buy a firearm. 

The bill comes after several other state and local governments have passed contentious gun-control measures in the wake of the February mass shooting at a Florida high school.

Amid a barrage of taunts from protesters calling him a "liar" and a "traitor" last month, for example, Vermont Gov. Phil Scott enacted the state's first major gun control measures during a heated signing ceremony at the Statehouse.

A conservative woman who recently graduated from Kent State University has received threats after she took aim at her school’s anti-gun policies in a photo shoot where she carried an AR-10 and wore a cap that said, “Come and take it.”

Kaitlin Bennett, a 22-year-old Second Amendment supporter from Zanesville, Ohio and founder of Liberty Hangout at Kent State, a student media outlet that promotes libertarian values, posed in front of the Kent Student Center for the tweet that has gone viral.  

“Now that I graduated from @KentState, I can finally arm myself on campus. I should have been able to do so as a student – especially since 4 unarmed students were shot and killed by the government on this campus. #CampusCarryNow,” she posted on Twitter Sunday.

Bennett told Fox News she wanted to condemn the school’s “insulting” policies.

“I wanted to draw attention to the gun policies on campus that allow guests to open carry, but not students,” she said. “I find it insulting that the school values the lives of their guests more than those attending the university for four years.”

The university has a rule against students, faculty, and staff carrying “deadly weapons.” But Kent State University spokesman Eric Mansfield told Fox News that because Bennett is no longer a student, she violated no policies.

“After graduation, she joined the ranks of our proud graduates,” Mansfield said. “So at the time of this photo, she and other graduates would be permitted to open carry on our campus.”

AT TOP 45 COLLEGES, NO CONSERVATIVES INVITED FOR COMMENCEMENT: REPORT

Mansfield noted that KSU has a full-time, certified police force of more than 30 sworn officers who protect the campus and the university was recently ranked the safest big college campus in Ohio and the 25th safest in the country, according to National Council for Home Safety and Security.

Bennett said even though she’s received death threats because of her post, she has no regrets.

Bennett told “Fox & Friends” Thursday morning she was offered a job by Blue Target Firearms as a result of the media attention.

“I have no apologies for my graduation photos,” she tweeted Tuesday. “As a woman, I refuse to be a victim & the second amendment ensures that I don't have to be.”

In another tweet, she made it clear her gun is an AR-10 and not an “assault rifle” as many had claimed.

“Don’t talk about gun control,” Bennett wrote, “when you can’t even get your facts straight.”

A federal judge ruled Sunday that anonymous teenage plaintiffs helping to challenge Florida's sweeping anti-gun law must identify themselves publicly, even as he acknowledged the order would probably expose them to intense leftist "vitriol" and "harassment."

In a surprising turn, U.S. District Judge Mark Walker even suggested that he personally wanted to side with the NRA, which wants to shield the young plaintiffs' identities, but said his hands were ultimately tied by court precedent.

"If it were entirely up to this court, the court would not hesitate to grant the NRA's motion," Walker wrote in his ruling. "One need only look to the harassment suffered by some of the Parkland shooting survivors to appreciate the vitriol that has infected public discourse about the Second Amendment. And this court has no doubt the harassment goes both ways."

The NRA filed the lawsuit on Second Amendment grounds soon after Florida lawmakers approved gun legislation that would raise the age to buy guns to 21 years old. The age restriction is one part of a larger anti-gun bill signed by Gov. Rick Scott in the wake of the February shooting at Marjory Stoneman Douglas High School that left 17 dead.

THIESSEN: CORPORATE BOYCOTTS OF NRA ARE REALLY BOYCOTTS OF UPSTANDING AMERICANS

Citing the harassment of one of its top Florida officials who was subjecting to threatening and profanity-laced emails and phone calls, attorneys for the NRA wanted to include a 19-year-old woman as a plaintiff in the lawsuit but wanted to keep her name confidential and instead identify her as Jane Doe.

The NRA also sought to include testimony from another 19-year-old man as well. The move was challenged by Attorney General Pam Bondi.

The NRA has been in the crosshairs of anti-gun activists for the past several months, with Parkland shooting survivor David Hogg leading boycotts of corporations and politicians who refuse to summarily cut ties with the organization.

Anti-gun rhetoric has markedly intensified as well. Earlier this year, a Florida billboard calling the NRA a “terrorist organization" was funded by a former White House staffer for President Bill Clinton. That criticism was echoed in March by Connecticut Democratic Gov. Dannel Malloy, who said the NRA has "in essence become a terrorist organization."

NRA BREAKS 15-YEAR FUNDRAISING RECORDS, FILINGS SHOW

Marion Hammer, a former president of the NRA and its top Florida lobbyist, said the NRA was "very disappointed" in the judge's decision, but said that it was "too soon" to know what steps the organization would take next.

"We're trying to shield these young adults from some of the most evil, hateful stuff you can imagine," Hammer said in an email. "... Individuals should be able to stand up for their rights and beliefs in the Second Amendment without having to expose themselves to harassment and bullying."

The Associated Press contributed to this report.

Lt. Col. Oliver North is set to become the president of the National Rifle Association of America, a process the NRA Board of Directors initiated Monday, the group announced.

North will be retiring from his role at Fox News effective immediately. He will be taking over the position occupied by Pete Brownell, who did not seek a second term as NRA president.

"I am honored to have been selected by the NRA Board to soon serve as this great organization's President," North said in a news release.  “I appreciate the board initiating a process that affords me a few weeks to set my affairs in order, and I am eager to hit the ground running as the new NRA President.”

NRA Executive Vice President and CEO Wayne LaPierre called North a "legendary warrior for American freedom, a gifted communicator and skilled leader." LaPierre called the North announcement "the most exciting news for our members since Charlton Heston became President of our Association."

North served 22 years as a Marine and was part of the National Security Council staff during the Reagan administration. He hosted a documentary series titled "War Stories with Oliver North" and was a contributor on Fox News.

NRA spokeswoman Dana Loesch congratulated North on his new position.

"Thrilled about the Oliver North news. A total warrior for freedom, this is the last person that anti-gun advocates would want as the new President of the NRA board," she tweeted.