Photo: Lea Suzuki / The Chronicle Photo: Lea Suzuki / The Chronicle

A former senior investigator says he was fired for blowing the whistle on his boss, San Francisco District Attorney George Gascón, who he alleged carried a gun while flying — in violation of federal law.

Gascón reacted with a “pattern of retaliation and harassment” that culminated in the termination of senior investigator Henry G. McKenzie on Oct. 30, 2017, according to the suit filed in U.S. District Court in San Francisco.

In the Nov. 24 filing, McKenzie says that Gascón — who is also the city’s former police chief — took a gun on board commercial flights repeatedly after becoming D.A. in January 2012.

According to the suit, members of the San Francisco District Attorney’s Office Investigators Association, which included McKenzie, discussed the “need to blow the whistle” on Gascón’s potential criminal violations in early 2017.

Sometime that spring, an investigator in the district attorney’s office contacted the Transportation Security Administration to report Gascón’s alleged unlawful travel with a firearm.

“The issue is flying armed while not being a peace officer, and flying armed when there was no need to” for law enforcement purposes, McKenzie’s attorney, Fulvio Cajina, told us.

Under federal law, peace officers who are armed while traveling are required to state that they are doing so for good reason — a reason related to their work — under penalty of perjury. The investigators believed that, as district attorney, Gascón was no longer an active peace officer and had no need to travel with a gun.

In the months after the TSA was notified, five of the Investigators Association’s seven-member governing body were either terminated or reprimanded. In all, according to the suit, “nearly half of the district attorney’s investigative department — or about 14 staff members — “were either terminated or forced to resign under intense pressure within a five-month span,” the suit said.

At a Sept. 5, 2017, training day at the Lake Merced shooting range, Gascón allegedly told the entire investigations staff that “there was a ‘cancer’ growing in the Bureau of Investigations and he was going to cut it out,” according to the suit.

Photo: Kat Wade / Special To The Chronicle 2010

In what was described as a rant, Gascón told the group that if anyone was going to talk to The Chronicle’s Matier & Ross, “they better make sure they had their facts straight” and that he would “be around a lot longer than anyone else” at the bureau.

The next day, on Sept. 6, 2017, McKenzie says he was placed on administrative leave and that an internal affairs investigation was pending.

McKenzie alleges he was removed from his job because he “was either a whistle-blower or had aided a whistle-blower.”

He was fired the next month, and in late February, McKenzie’s termination was upheld by the D.A.’s office after an administrative review. McKenzie has since found a new job.

In the meantime, according to the lawsuit, “federal authorities have launched a criminal investigation into defendant Gascón.”

TSA spokeswoman Lorie Dankers declined comment, saying the agency “cannot provide any additional detail beyond what is in publicly available documents.”

The TSA website spells out the specific criteria required for law enforcement “flying armed,” and simply being a cop doesn’t cut it. Among other things, the person must be authorized “to have the weapon in connection with assigned duties” and “have completed the TSA Law Enforcement Officer Flying Armed Training Course.”

The person must also have a particular reason, such as being on protective duty, conducting a hazardous surveillance operation or handling a prisoner. Also, according to the website, it’s not good enough to carry a weapon while attending “training, conferences, police week, memorial services (or on) personal travel.”

When asked whether Gascón had been carrying a weapon while flying — and on what grounds — D.A. spokesman Max Szabo declined to comment, telling us, “We can’t comment on a former employee’s lawsuit.”

Gascón, by the way, has announced he will not seek a third term next year, citing his need to care for his elderly mother in Southern California.

Curtain rising: Being flush with a nearly $15 billion budget surplus had some Democratic lawmakers in Sacramento already proposing tens of billions of dollars in new social and educational programs during the opening week of the new legislative session.

Proposals submitted by lawmakers in the first week ranged from more funding for schools to extending Medi-Cal eligibility to adults living in the country illegally.

But just as fast as the spending is being proposed, key lawmakers are tapping the brakes.

“We have to watch the bottom line,” said Assembly Budget Committee Chairman Phil Ting, D-San Francisco.

“The California economy is strong, but we have been growing for eight years, and that is two years over the historic cycle for another recession,” Ting said. “We don’t want to start spending and then go through the dramatic cuts we had to in the last recession, which came to about $20 billion a year.”

Photo: Russell Yip / The Chronicle 2017

Gov.-elect Gavin Newsom appears to agree.

“The Legislature laid out a wish list, with no one believing we can do everything at once,” Newsom said.

Instead, look for one-time spending on specific tasks, such as cleaning out the state’s fire-prone forests and brushlands, along with a string of “down payments” on new programs, including Newsom’s own pet project to increase universal preschool.

“Within our means and with historic reserves,” Newsom said, in what is likely to be the most heard statement of the budget battle.

San Francisco Chronicle columnists Phillip Matier and Andrew Ross appear Sundays, Mondays and Wednesdays. Matier can be seen on the KPIX-TV morning and evening news. He can also be heard on KCBS radio Monday through Friday at 7:50 a.m. and 5:50 p.m. Got a tip? Call 415-777-8815, or email matierandross@sfchronicle.com. Twitter: @matierandross