In a first for the tech giant, Google filed a consumer protection lawsuit to shield the vulnerable and unsuspecting from what it called a “nefarious” scheme: the sale of adorable, but imaginary, puppies.

The lawsuit, filed Monday in U.S. District Court in San Jose, Calif., claims that Nche Noel Ntse, a Cameroon man, defrauded would-be puppy buyers using a range of Google services, including Gmail accounts, Google Voice numbers and advertisements.

Mr. Ntse lured his victims with “adorable” and “alluring” photographs of purebred puppies, together with “compelling testimonials from supposedly satisfied customers” that exploited the high demand for puppies in the United States during the coronavirus pandemic, according to court documents.

Google says it spent more than $75,000 to “investigate and remediate” Mr. Ntse’s activities, and is suing him for financial damages, citing harm to the company’s relationship with its users and damage to its reputation.

“It seems like a particularly egregious abuse of our products,” Michael Trinh, a lawyer for Google, said by phone on Monday.

The company says it prevents 100 million harmful emails from reaching users daily, but Mr. Trinh said he hoped the suit would go further, making an example of Mr. Ntse. Google decided not to pursue criminal charges in the case because it believed civil litigation would be a faster remedy, Mr. Trinh added. “It’s an ongoing fight.”

The case is Google’s first consumer protection lawsuit, José Castañeda, a spokesman for the company, said. He added that based on the sprawling network of sites run by Mr. Ntse, Google estimated that the victims lost more than $1 million in total.

Google’s legal action comes after the pandemic caused a surge in demand for pets, as well as an increase in schemes capitalizing off that desire.

Last year, consumers reported losing more than $5.8 billion to fraud, an increase of more than 70 percent from 2020, according to data from the Federal Trade Commission. Online shopping scams in particular skyrocketed during the pandemic, according to the Better Business Bureau. The group estimates that in 2021, pet-related fraud accounted for 35 percent of such reports.

Google first became aware of Mr. Ntse’s activities around September 2021 after receiving a report of abuse from AARP, an advocacy group for older Americans.

According to the report, a person living in South Carolina seeking a dog contacted Mr. Ntse by email after visiting a website he operated, now defunct. After corresponding with Mr. Ntse by email and text, the person later sent him $700 in electronic gift cards, the report said, adding, “Victim 1 never received the puppy.”

According to the case summons, Mr. Ntse is based in Douala, a port city of more than two million people in Cameroon. He ran other websites, including one that purported to sell marijuana and prescription opiate cough syrup, the lawsuit says.

“When you go to buy a puppy, you don’t expect a criminal to be on the other end,” said Paul Brady, who runs PetScams.com, which tracks and reports websites that falsely claim to sell animals.

Scammers, often located outside of the United States, post photos and videos of puppies at low prices and request upfront online payments and sometimes additional invented costs, like animal quarantine or delivery fees.

Such schemes have “exploded” in the past two years, Mr. Brady said, as scammers capitalized on people’s loneliness and took advantage of lockdowns that limited their ability to travel far from home to collect a puppy.

“People are sitting alone, and they want the company of an animal,” he added, recalling a particularly shocking incident in which one woman spent $25,000 attempting to purchase a Pomeranian puppy.

For Rael Raskovich, 28, the experience of being cheated by an online pet scheme was devastating.

About a year ago Ms. Raskovich, who works in the mortgage industry, had just moved to South Carolina and was hoping to buy her first puppy: a Golden Retriever.

She explored her options, ultimately filling out an online form, now defunct, that included detailed questions about her plans to care for the animal, she said, which led her to believe that the process was legitimate.

She wired a $700 deposit to the seller, who sent her a video of what she thought was her soon-to-be puppy. She bought toys and a dog bed.

Then, she said, the seller claimed to need an additional $1,300 for a coronavirus vaccination for the dog and an air-conditioned shipping crate. Ms. Raskovitch said she was told to expect a call from Delta Air Lines, which the seller claimed would be transporting the animal — but when she called to confirm, the airline told her it does not ship animals.

“Then I was like, ‘OK, this definitely isn’t legitimate,’” she said, adding that she cut off communication. The identity of the seller was never determined.

“You get ready for this new addition in your life,” Ms. Raskovich said. “It sucks.”

Kirsten Noyes contributed reporting.