Barely three months into her new post as an FBI supervisor in Los Angeles in 2015, Jill Sanborn had just sat down for a holiday luncheon with local law enforcement when she got the call: Two shooters were terrorizing a work party about an hour away in San Bernardino.

The rampage — by a couple inspired by Islamist terror groups — killed 14 people in what was then considered the deadliest attack in the U.S. since 9/11. It opened a new chapter in homegrown radicalization and is a lingering memory for the new special agent in charge of the FBI's Minneapolis field office.

"I always wonder if there was something somebody saw — maybe it was odd behavior, or remarks that they made to someone — that could have helped us counteract that," Sanborn said recently in her Brooklyn Center office.

The 20-year FBI veteran brings to the office a breadth of counterterrorism experience that has dominated her time at the bureau. She takes over an office that has historically been one of the FBI's busiest for such cases and at a time when the FBI maintains some several thousand active terrorism probes nationwide, according to recent testimony from its director.

"What makes terrorism different from other priorities is that lack of tolerance for not getting it right," said Sanborn, who keeps a copy of the 9/11 Commission's final report near her desk.

"Nobody expects the FBI to stop all bank robberies from happening — but with terrorism comes a very high standard unlike any threat we face."

Sanborn, 47, is the second woman to lead the FBI's Minneapolis office, which also covers the Dakotas, and she is one of nine women in charge of the FBI's 56 field offices in the country. FBI leaders have described its lack of diversity as a crisis, and Sanborn's own story is one of an FBI career that nearly never started.

She grew up in a small southwestern Montana town, with three older brothers, a mother who was a two-time Olympic skier and a father who taught psychology at a nearby college. Federal service appealed to Sanborn at an early age — she worked as a Senate page for former U.S. Sen. Max Baucus of Montana — and she graduated with a business degree from the University of Portland before taking her first job as an internal investigator for the Los Alamos National Lab in New Mexico.

There, Sanborn worked closely with an investigator from the Inspector General's Office who urged her to consider a career with the FBI. "I remember thinking 'I'm a small-town Montana girl, there's no way the FBI would hire me,' " Sanborn said. "But they hired me."

First assignment

In more than one way, Sanborn's first assignment, at the FBI's Phoenix office, helped shape the next 20 years of her life. There, she met her husband, Mike Sanborn, a special agent whose expertise has been investigating violent crimes, fugitives and stolen valor cases. Both Sanborns are now working out of the Minneapolis office.

Also in Phoenix, Sanborn embarked on the beginning of a globe-trotting career working terror cases, transferring to her first counterterrorism squad the day of 9/11. The FBI later selected her for its "fly team," a small coterie of agents and analysts with expertise in terrorism who can be deployed anywhere in the world to help with such cases. She also worked as a high-level liaison to the Central Intelligence Agency and went on to be responsible for all of the FBI's overseas terror operations.

"Pick a nasty spot in world — Jill's been to a lot of them," said Grant Mendenhall, a longtime supervisor and colleague who now leads the FBI's Indianapolis office. "To be able to understand how things work outside of Minnesota, North Dakota and South Dakota is a very valuable perspective for her to have."

Mendenhall said Sanborn's collaborative instincts also paired well with the "team sport" he described as terrorism investigations.

That philosophy was on full display in the harried aftermath of the San Bernardino attacks in December 2015.

Upon arriving at the scene, Sanborn said she first noticed the level of familiarity among federal agents and local authorities who were working the case.

"I knew instantly that because of those relations, no matter where the attack investigation took us, we were going to be OK," Sanborn said.

Alberto Martinez, deputy director of the Orange County Intelligence Assessment Center, one of the 79 "fusion centers" created to link multiple levels of law enforcement after 9/11, credits Sanborn for helping forge those partnerships well before crisis struck. It was far from the well-worn stereotype of agents hoovering up local cases, Martinez said.

"Her position here actually established a strong bond between local law enforcement and the FBI," Martinez said. "And that's all credit due to her. Now, we're being used as an example of how local law enforcement and the FBI can work well together during significant incidents."

The experience also underscored a commitment to maintaining a work-life balance that Sanborn hopes to demonstrate to her new workforce. While she could have stayed overnights at the San Bernardino command post, she drove the 70 minutes home each night to, at a minimum, be able to spend evenings with the couple's two Labradors, Duke and Max.

Sanborn succeeds Rick Thornton, who retired earlier this year and has since taken a job with the Minneapolis Federal Reserve. She spent much of last week brushing up on a new priority — Indian country — while visiting several places in South Dakota.

Before his departure, Thornton predicted a rise in domestic extremism that the FBI will need to reckon with. Sanborn said she has so far not received an assessment of such potential threats, but vowed to use the same "tools and techniques" to investigate, despite not having the same criminal statutes with which to work as international terror cases.

Persistent attacks on the FBI's credibility by government officials continue to pose a challenge for anyone whose job it is to manage morale at the bureau.

The issue surfaced one even­ing during a visit with participants in the FBI's citizen's academy. Afterward, Sanborn hung back for a presentation by an agent who helped win a conviction in a case involving the smuggling into Iraq of parts used for explosive devices that killed U.S. service members.

The agent recalled a letter sent to him by a member of one fallen soldier's platoon, thanking the agent for his work. Before taking the witness stand at trial, the agent recalled, he visited the soldier's grave to preview his testimony.

"That's why we do what we do," Sanborn said. "That's the stuff that really matters."

Twitter: @smontemayor