A mild-mannered accountant many would consider a hero of our time reached into his jacket pocket and produced a black electronic device topped by five antennas when a fellow passenger began jabbering on a cellphone.

The jabberer’s phone suddenly went dead along with any other cellphones aboard this car of an inbound train on Chicago’s CTA Red Line. The accountant enjoyed a peaceful few moments on Tuesday morning before the jabberer announced that he was a police officer.

Other plainclothes cops joined in making the arrest. The accountant, 63-year-old Dennis Nicholl, was escorted off the train and booked on a felony charge of unlawful interference with a public utility. His Chinese-made cellphone jammer was vouchered as evidence.

After being held overnight in the Cook County jail, Nicholl appeared in criminal court before Judge James Brown. Nicholl stood as someone who had acted out a fantasy shared by many of us who have found ourselves trapped with annoying cellphone jabberers.

“Ah, cellphone police,” the judge said.

The prosecutor, Erin Antonietti, noted, “Well, a self-proclaimed one.”

The suggestion was that Nicholl had been acting as some kind of vigilante.

A true cellphone vigilante named Jason Humphreys had been arrested outside Tampa, Florida, back in 2013. One reason such jamming has been declared illegal became apparent after deputies pulled over the SUV he was driving.

“Deputies reported that communications with police dispatch over their… two-way portable radios were interrupted as they approached the SUV,” notes a subsequent report by the Federal Communications Commission.

The report continues, “Mr. Humphreys admitted that he owned and had operated a cell phone jammer from his car for the past 16 to 24 months. An inspection of the vehicle revealed the cell phone jammer behind the seat cover of the passenger seat. Mr. Humphreys stated that he had been operating the jammer to keep people from talking on their cell phones while driving.”

Humphreys was fined $48,000 for presuming to be what was indeed a sort of cellphone police, and for interrupting the communications of the real police.

But Nicholl does not appear to have been seeking to modify the behavior of others so much as simply to secure a little peace and quiet on his way to and from his job as a supervising financial analyst at the University of Illinois.

Nicholl seems to have had his present jammer at least since 2014, when a fellow commuter named Brian Raida happened to see him take it out on a morning train. Raida’s phone went dead, along with those of the other passengers.

“Everyone was looking at their phones like—what the hell?” Raida would tell The Chicago Tribune.

Raida would recall telling Nicholl, “Hey dude, nice jammer.”

Nicholl is said to have grinned, apparently not imagining that Raida had taken a candid photo of him holding the jammer. Raida seems to be among those who view such jamming as an unwarranted intrusion and perhaps even a hazard in this era when we are so dependent on our cellphones. He sent the photo to the police with the opinion that a jammer is less a hero than a menace of our time.

“This guy needs to be stopped,” Raida said in a subsequent online posting.

More complaints seem to have followed, along with considerable discussion online. A commuter saw Nicholl settle onto an evening train with a bag containing Old Style beer. Nicholl took out the black gizmo with the five antennas, and all the cellphones within 50 feet were silenced. Nicholl then rode homeward in peace, sipping his brew.

Early Tuesday morning, what was termed a “mission team” of cops and federal agents staked out a station where Nicholl had been seen. They spotted him and a plainclothes cop trailed him onto a train. The cop began jabbering on his cellphone and watched Nicholl produce the jammer.

The cop’s phone went dead. Nicholl got a few more moments of peace before his arrest. He reportedly admitted to police that he was aware such jammers are illegal. He confided that a previous one he ordered had been confiscated by customs. He had simply ordered another one, by the looks of it at least similar to the “GG4 Universal 2G, 3G, 4G All Cell Phones Blocker” available for $479 on such sites as Jammer.

“GG4 is a brand new word in signal jamming technology,” says the blurb. “Will surely block all the cell phones from old 2G phones to the latest and the most advanced 4G compatible smartphones. GG4 will knock out even HTC Droid or iPhone 5 in no time, any other cell phone blocker cannot achieve that.”

What the blurb does not say is that such devices can land you behind bars. The Cook County jail is hardly a place a mild-mannered accountant would want to spend the night, but there was one blessing: Cellphones are banned not just in the lock-up but in the courthouse.

Had anyone started blathering on a cellphone during Nicholl’s hearing, a court officer would have confiscated it and perhaps taken the offender into custody. Nicholl was ordered held in lieu of $10,000 bail for having used his jammer to effect his own personal cellphone ban during his workday commute.

By nightfall, Nicholl had posted bail and returned jammer-less to the realm where people are forever jabbering. He returns to court for a hearing on March 15, an accused felon in the eyes of the law and an annoyance—even a menace—to those who believe in the right to chat. His detractors would not be wrong to suggest that chaos would result if everybody packed a jammer and used it as whim dictated.

But Dennis Nicholl nonetheless remains a hero of our time for those who know exactly how he feels.