As a violent mob stormed the U.S. Capitol, retired Chicago firefighter David Quintavalle was about 700 miles away, shopping at an Aldi grocery store for the final ingredients for his wife’s birthday dinner.

The 63-year-old’s mind was on the menu — filet mignon and lobster — and not insurrection.

But a man resembling Quintavalle with salt-and-pepper hair and a “CFD”-labeled beanie was among the rioters. In a video, the man pelted police with a fire extinguisher, striking at least one officer.

In the days following the attack, Internet sleuths who have hunted down those who participated in the Jan. 6 riot mistook the man for Quintavalle. Soon, people were calling Quintavalle’s cell and home phone, harassing his son, a Chicago police officer with the same name, and lurking outside Quintavalle’s home.

“It’s created havoc in my life, for my family, my wife, all of us,” Quintavalle told The Washington Post. “It’s just grueling us. Someone should be held responsible for this. It’s just not right that you live your life correctly, follow all the rules, and this is what happens.”

Some Trump allies have speculated that antifa was responsible for inciting violence and storming the U.S. Capitol on Jan. 6. No evidence supports this claim. (The Washington Post)

Online amateur investigators have identified and shared information on social media about people in photos and videos at the Capitol, leading to a portion of the more than 100,000 tips submitted to the FBI since the mob attempted to stop the counting of votes in the presidential election.

The hurried pace of new information has also increased the dissemination of incorrect names and targeting the wrong people.

Since the attack, John Scott-Railton, a researcher at the University of Toronto’s Citizen Lab, an Internet watchdog, has repeatedly warned his burgeoning 137,000 followers to not share identities that have not yet been verified.

“Tweeting unconfirmed identities is NOT necessary; you may hurt someone in ways you cannot take back; exposes you to legal risk; you may get banned,” Scott-Railton tweeted.

The victims of such false accusations include martial artist and actor Chuck Norris. A photo circulated online of his doppelganger among those storming the Capitol. The baseless speculation was shot down by his manager Erik Kritzer.

“This is not Chuck Norris and is a wannabe look alike although Chuck is much more handsome,” Kritzer told USA Today. “Chuck remains on his range in Texas where he has been with his family.”

Quintavalle’s attorney, John L. Nisivaco, said he provided the FBI with evidence of his client’s alibi — the receipts for his grocery run and Home Depot visit.

Federal authorities allege the man who threw the fire extinguisher is Robert Lee Sanford Jr., 55, a recently retired firefighter from Chester, Pa. He was charged Thursday with assaulting officers engaged in official duties, knowingly entering a restricted building and disruptive conduct on Capitol grounds.

But Quintavalle still receives hateful calls and messages calling him a “murder” and “terrorist.” A police officer is stationed outside Quintavalle’s home for his safety, Nisivaco said.

“He is an absolute stand-up guy, a husband, a father of two,” Nisivaco said. “By all accounts, he has a spotless reputation. And now he’s left to clear his name and restore his reputation by himself, and what an unbelievably arduous task that is.”

For Becky’s Flowers, a small three-person flower shop in Roseville, Calif., harassment came in the form of one-star ratings on Yelp and Google and hateful comments on their social media pages.

The store shares the same name as a flower shop in Midland, Tex., owned by Jenny Cudd, who was arrested after she bragged on Facebook “We did break down … Nancy Pelosi’s office door.”

The California shop was able to get most of the negative reviews removed once employees explained the misunderstanding, assistant manager Kali Mitchell said.

“Most of them were resolved by us messaging them and saying ‘hey, thank you for looking out for your country but you’re directing it at the wrong company. We’re in a completely different state,’ ” Mitchell said. “And most of those people that saw that removed that and apologized profusely just because they got the wrong place.”

Once customers realized the store was being unfairly targeted, orders surged, Mitchell said.

“I’ve had so many orders that are just ‘we want to support the store’ and ‘we’re sorry this is happening,’” Mitchell said. “It’s been almost overwhelming with how nice people are being.”

While for some people the cases of mistaken identity have been a nightmare, Washington, D.C.-based comedian Kevin Seefried has found humor in sharing the same name as a Delaware man identified as carrying a Confederate flag in the Capitol.

The other Kevin Seefried was arrested Thursday on charges of trespassing, violent entry and disorderly conduct on Capitol grounds

Before he knew they were name twins, the comedian mocked the widely circulated photo of the flag-wielder.

“To be fair, I guess their heritage is based on treason,” he commented on Twitter the day of the riot.

By Thursday, when the man in the picture was named and arrested, Seefried pinned a link to a stand-up set mocking Confederate sympathizers and wrote: “proof it ain’t me.”

“To have a Confederate flag in this day and age is tone-deaf and wrong and shows a lack of understanding of history, lack of affection and care for other people in the world,” Seefried told The Post.

Seefried said only a few people mistook him for the arrested man, and on those occasions, Seefried replied he concurred with his confused antagonizers.

When one user cursed at Seefried, he answered “wrong kevin seefried bro (but agreed, [expletive] 'em).”

Mostly, he has joked with people — including a man with the same name as convicted sex offender Jeffrey Epstein — about the situation.

“I think that me being confused with that person and whatever minimal effect that will have in my life is nowhere near what so many other people are having to deal with because of prejudices in the world,” he said in an interview. “I think there are more pressing issues than a guy named Kevin being confused with another guy named Kevin.”