New England Patriots quarterback Tom Brady, right, with his trainer Alex Guerrero on the sideline before the Super Bowl game against the Atlanta Falcons on Feb. 5, 2017, in Houston, site of Super Bowl LI. (Damian Strohmeyer via AP)

(RNS) — A few years ago I went to the grocery store and ran into some cultists.

They didn’t look like end-times cultists at the time. Instead, they appeared to be do-gooders — warmhearted local volunteers who were rescuing kittens.

They parked their mobile cat shelter outside the local Kroger and let kids inside to play with the kittens — in hopes those kids could pester their parents into taking one home.

(My daughter tried. It didn’t work.)

Still, they were nice cat people.

Not long afterward I talked to Rachael Gunderson. Rachael had joined the cat rescue group — known as Eva’s Eden — about a decade earlier, in Bellingham, Wash.

Back then, the group was called the Gates of Praise, a run-of-the-mill Pentecostal church, known for its exuberant worship and creativity. The church was like a family and made her feel welcome from the start.

Especially Pastor Sheryl – Sheryl Ruthven, the church’s tall, blond charismatic leader.

“I heard Sheryl preach that day, and I was hooked,” she told me.

At first, things went well. Rachael spent every spare hour at the church, soaking in Pastor Sheryl’s teaching. Pastor Sheryl showered Rachael with love – and told her that God had great things in mind for her.

But before long, things got crazy. Pastor Sheryl started claiming to be a prophet, then a reincarnated Mary Magdalene, and then a new Messiah. She made followers kiss her feet and drink her blood mixed with their Communion wine.

Then there were the cats.

Pastor Sheryl thought stray cats were angels in disguise — and that church members should dedicate their lives to rescuing them. When the end times came, those cats would transform back into angels and return the favor — saving church members from the end of the world.

In other words, Apocalypse Meow.

Gunderson bought it all.

“It’s like once you take one sip of the Kool-Aid, you keep drinking,” she said.

I met Gunderson while reporting on Eva’s Eden. She’d left the group by then and rebuilt her life. Still, she was haunted by her past.

How could this have happened, she wondered.

I wondered the same thing. How does a normal congregation turn into a cat-worshipping cult of personality?

Ben Zeller, assistant professor of religion at Lake Forest College, just north of Chicago, says that a charismatic leader is key. In a group like Eva’s Eden, follower members are often more tied to the leader than to theology, said Zeller, who studied the Heaven’s Gate cult in Arizona.

So they will follow their leader, even if it means betraying their own beliefs. After a while, they are too invested to leave.

“There are plenty of people who are along for the ride. It’s just that it’s amazing what people will do when they are along for the ride — if it means giving up their money or control over their lives or their finances, their romantic relationships or, in suicidal groups, their lives,” Zeller told me.

That line — “there are plenty of people who are along for the ride”— has come to mind recently, with revelations of a rift between the New England Patriots and the “cult of Alex Guerrero.”

Tom Brady’s friend and trainer Alex Guerrero on the New England Patriots sideline. Video screenshot

Guerrero, a former missionary turned charismatic fitness guru, is Tom Brady’s miracle man, credited with allowing the star quarterback to play at a top level into his 40s. The two have teamed up to spread the Gospel of TB12 — in a best-selling book and TB12, a lucrative training and fitness brand.

In TB products and promotions, Guerrero shares almost every moment of Brady’s life — what he eats, how he exercises and rests, how he mentally prepares for games. He’s even godfather to Brady’s son.

He’s a “big part of what I do,” Brady said after news broke that Guerrero was banned from team flights and the sidelines during Patriots games.

As Sports Illustrated put it, they’re closer than most married couples.

“This season marks Year 13 for Brady and Guerrero, a pair who spend more time together than most married couples, swearing to remain faithful in health and in better health,” wrote Greg Bishop. “They opened their TB12 Sports Therapy Center up the hill from Gillette Stadium in 2013 and started selling products last year, peddling lemon protein bars made with Himalayan pink salt, resistance bands built with ‘surgical-grade dipped latex tubing’ and athlete recovery sleepwear that fits ‘next-to-skin without the squeeze.’”

But Guerrero also has issues.

“Tom Brady’s Personal Guru Is a Glorified Snake-Oil Salesman” is how Boston magazine put it.

He was twice investigated by the Federal Trade Commission. Claimed to be an MD when he’s not. Marketed a juice he claimed would cure cancer and another that was supposed to stop concussions.

He was also accused of defrauding investors. And of stealing hundreds of thousands of dollars from another client — a client who also made Guerrero godfather to his son.

In other words, he sounds a lot like a cult leader.

Now he’s tied at the hip with probably the greatest quarterback ever and one of the wealthiest and most powerful star athletes in the world.

And he’s using that fame to spread the Gospel of TB12, recruiting other players to join their cause and spreading the message around the world.

Some of it works.

Brady’s exercises, which stress flexibility, and his healthy eating habits have helped him remain at the top of his game at 40, a rare feat in the NFL.

But the questionable claims about Guererro’s methods remain — especially the high profile they get from their ties to Brady.

Given Guerrero’s history, there’s cause for concern, says Boston Globe columnist Dan Shaughnessy.

Guererro reminds Shaughnessy of Dr. Eugene Landy, the quack doctor who nearly destroyed Brian Wilson of the Beach Boys.

After recounting Guerrero’s past sins and alleged misconduct, Shaughnessy issues a warning.

“If it works for Tom, that’s great. But Belichick is wise to put some space between the Patriots and the cult of Alex Guerrero,” he wrote, referring to the Patriots coach.

“We all love QB12, but Tom Brady is becoming Tom Cruise right in front of our eyes. It’s only a matter of time before he jumps on the couch with Oprah in defense of Alex Guerrero. Go back to last year’s Brady interview on WEEI about the perils of Western medicine, and last summer’s bottom-feeder appearance with Tony Robbins.”

Back to the cat cult for a moment.

Most of its adherents ducked me as I reported on their group. But I eventually reached Georgia Snow, Ruthven’s mom, one of her daughter’s most devoted followers.

Why don’t you leave us alone, she said. Isn’t there religious freedom in America?

“We do nothing but good,” she told me. “And yet we have people who try to destroy that.”

Brady seems to be doing much of the same. Guererro’s ideas work for him. So why knock them?

This is the hard part of religion reporting. And this story is definitely a religion story.

Brady’s ties to Guerrero are based on belief and his own experience – not science. And the two are closer than most trainers and athletes. Guerrero is, in effect, Brady’s spiritual adviser and guide.

There’s a difference between beliefs that are weird and beliefs that are harmful and abusive. Guerrero seems to dance on that line and has crossed over it more than once.

Now Brady’s boss is threatening his beliefs.

When that happens, all hell can break loose.

For 17 years, the Patriots — and full disclosure, I am a big fan — have been nearly unstoppable. Five Super Bowl titles and more wins than any other football team in that era. And they seem poised to add a sixth.

But the ties that bind the team’s quarterback and coach are fraying.

And a snake oil salesman may bring the whole thing crashing down.

Get your popcorn.

This will be interesting to watch.

(Bob Smietana is a veteran religion writer based in Nashville, Tenn., and former chairman of the Religion News Service board of managers. The views expressed in this opinion piece do not necessarily reflect those of RNS.)