Tennessee: A possible jihadist in Tennessee. A white supremacist in South Carolina. A Ph.D. student dropout sowing terror at a Batman movie in Colorado.
In one day, three alleged or convicted mass killers shared headlines in America, with a common thread running through all their stories -- easy access to firearms.
The coincidence has rekindled calls for Congress to finally beef up the nation`s gun laws -- something it failed to do after the Newtown, Connecticut elementary school shooting in 2012 that left 20 children dead.
"This is one of the most significant days in American history when it comes to gun violence," said Dan Gross, president of the Brady Campaign to Prevent Gun Violence, in a statement.
"The same day a jury handed down its verdict on a man for carrying out mass murder in a Colorado movie theater, another went on a deadly rampage killing four American Marines," he said.
"If this doesn`t cause policymakers to stop and think about the impact of gun violence in our country, what will?"
Gross was referring to James Holmes, 27, the one-time post-graduate neuroscience student who killed 12 people and wounded 70 others during a midnight screening of "The Dark Knight Rises" in Aurora, Colorado in July 2012.
He was convicted on a staggering 165 counts Thursday, the same day that Kuwaiti-born, American-raised Mohammad Youssuf Abdulazeez, 24, shot and killed four Marines in Chattanooga, Tennessee before dying in a shootout with police.Investigators say they are looking into "every possible avenue" in the case -- including whether Abdulazeez might have been connected to any global terrorist organization.
Gross could also have cited Dylann Roof, 21, charged with the June 17 massacre of nine blacks during evening Bible study at the historic Emanuel African Methodist Episcopal Church in Charleston, South Carolina.
Roof, who allegedly hoped the bloodbath would incite a race war, appeared Thursday in person before a judge who set July 11 next year as the tentative start date for his trial.
Mass killings -- defined by the FBI as those with at least four victims -- account for only about one percent of all murders in the United States, according to an analysis of FBI data by the newspaper USA Today.
But they nevertheless occur about every two weeks, the newspaper said. Often they grip Americans` imagination like few other crimes.
"Easy access to increasingly lethal firearms is the one factor that is almost constant in these attacks," said Josh Sugarmann, executive director of the Violence Policy Center in Washington.
"Lives are lost, families are devastated, and communities are scarred -- yet all too often we look for answers while ignoring the very tools that are commonly used to perpetrate these heinous acts."
Under the Constitution, every American is entitled "to keep and bear arms" -- a tenet jealously guarded by millions of law-abiding gun owners as a symbol of liberty and a foil against tyrannical government.
The December 2012 tragedy in Newtown -- in which six educators also died -- spurred President Barack Obama to demand tighter controls on the sale of military-style assault rifles like the one used by 20-year-old shooter Adam Lanza.But such is the political clout of the National Rifle Association (NRA) and the gun industry on Capitol Hill that legislation to mandate background checks for all gun sales -- not just those at federally licensed gun shops -- never cleared the Senate.
Since then, a Pew Research Center poll in late 2014 revealed -- for the first time in more than two decades -- more support among Americans for gun rights (52 percent) than gun control (46 percent).
Even with limited background checks, there is no guarantee that they can halt the sale of a weapon to someone known to law enforcement.
Such was the case for Roof, who managed to get the 45-caliber Glock used in the Charleston massacre thanks to lapses in the FBI`s background check system, FBI director James Comey has acknowledged.
Roof bought the gun within weeks of being busted on a drugs rap that should have blocked the sale. Yet the FBI never got details of the arrest within a three-day window for completing a background check.
"This rips all of our hearts out," Comey told a group of US journalists in Washington a week ago. "We are all sick this happened."
Investigators have yet to disclose how Abdulazeez got hold of the "multiple weapons" they say he used to carry out Thursday`s shootings in Chattanooga, which occurred just before the Eid al-Fitr holiday that marks the end of Ramadan.
But in the months prior to his Colorado rampage, Holmes managed to buy two Glock pistols, a semi-automatic rifle, a shotgun and 6,300 rounds of ammunition, in person and online.
He did so entirely legally, a federal agent testified at Holmes` preliminary hearing in 2013.