In the aftermath of the mass shootings in West Texas, first El Paso and then Midland-Odessa, the flood of calls surged into the federal government's National Threat Assessment Center, many of them tips on how -- hopefully -- to stop further bloodshed.
Calls were already steady, about 20,000 a week, but then jumped to as much as 30,000 after the carnage -- 22 dead in El Paso, eight dead in the Permian Basin, including the shooter.
In Dallas, at least a dozen FBI agents are now assigned to investigate what the bureau calls "threat-to-life" cases in the Metroplex.
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"And we are working through the volume, as well as we can, by trying to prioritize based on the level of threat to life," said Matt DeSarno, the new special agent in charge of the FBI's headquarters in North Texas.
"It's a challenging job because none of us want to miss anything. We don't want to have not taken some investigative step or identified some dangerous person," DeSarno said.
The calls that filter from the threat assessment center in Washington to the Dallas office range from tips of impending danger to concerns over a troubling post on social media.
For DeSarno, and the agents serving under him, it's just one of many roles they work to try to keep North Texans safe.
The SAC has in the past led the fight against violent street gangs in Chicago and, more recently had operational oversight of FBI counter-terrorism investigations throughout the world.
But the most troubling counter-terror threat right now, DeSarno said, are the so-called "lone wolf" actors, like the ones in El Paso and Midland-Odessa, and Brian Issack Clyde, the ex-veteran who opened fire on the federal courthouse in Dallas in June.
No one was hit in that attack, except for Clyde, who died when he was struck by return fire from guards.
"In the counter-terrorism threat landscape right now, detection of lone actors is the most difficult," DeSarno said.
That is because they typically don't communicate their plans with others, leaving fewer chances for law enforcement to intervene.
In an effort to curb the violence, DeSarno said, social media companies in the United States are working closer with law enforcement when they spot a post that seems to convey a threat.
But like law enforcement, those companies are overwhelmed by the amount of traffic on social media.
It's like "a needle in the haystack, or even a needle in a stack of needles, problem," DeSarno said.
He said the FBI has reinforced its commitment to check out everything that comes its way -- a troubling tweet, a Facebook comment, a phone call to the bureau.
"There is a volume challenge, but we would certainly rather people tell us, than not tell us," DeSarno said, adding, "I think where we see the best benefit is when someone who is really close to another person, who knows them well, maybe as a relative, provides meaningful information."
In the weeks after the El Paso shootings, authorities acting on tips from across the country had arrested more than two dozen people, all suspected of threatening some type of attack.
Such arrests are only possible, the FBI says, if the public keeps a watchful eye for peculiar behavior -- anger issues, depression, talk of hurting people -- that a would-be attacker is commonly known to exhibit in the year leading up to violence.
If that describes someone you know, law enforcement -- whether it be the FBI, state officers or local police -- wants to hear from you.