Terrie Peacock wiped away tears streaming down her face Tuesday as she recalled the distress and shock she felt when a San Mateo pet groomer emerged from an appointment with her year-old puppy, Henry, with blood foaming from the pooch’s mouth.

After their beloved dachshund died, suffering from two broken ribs and a punctured lung in what was supposed to be a routine nail-trimming at PetSmart, the owners are hitting the national pet retailer with a lawsuit.

“It’s been a living nightmare. We treat our pets like children,” Peacock said as she held her other dachshund, Bella, in her lawyer’s Burlingame office. PetSmart “knew that there were others that believed that their pets had been harmed and they did nothing about it. And as a result, our son died.”

Peacock and Stefan Zier, her partner, filed a wrongful-death lawsuit Tuesday against PetSmart and the company groomer arrested on suspicion of killing Henry, citing “an alarming number” of serious injuries and sometimes deaths after appointments at PetSmart offices across the nation.

“I was helpless. He was dying right in front of us,” Zier said of the moment when he saw Henry struggling to breathe in the lobby of the PetSmart offices in San Mateo. “What we want from this is there to be systematic change. We want these people (groomers) to be trained.”

Juan Zarate, a 38-year-old San Francisco resident, was arrested in mid-May at the store in the 3500 block of South El Camino Real after it became evident that “deliberate actions committed by Zarate likely contributed to the animal’s death,” said Sgt. Richard Decker of the San Mateo Police Department.

Zarate was charged with felony animal cruelty. He pleaded not guilty, posted bail and is awaiting trial, said Alison Cordova, the attorney representing the couple.

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Peacock and Zier said they were never given an explanation by Zarate or PetSmart as to how Henry suffered the extensive injuries that led to his death, Cordova added.

A PetSmart representative declined to answer questions about the case, saying in a statement, “As a practice, PetSmart does not comment on pending litigation.”

The bereaved couple say the lawsuit isn’t about money. They don’t want anyone else to have to deal with the trauma they’ve experienced since Henry’s death, Zier said.

The organization People for the Ethical Treatment of Animals receives complaints about incidents in which pets are killed or injured during grooming at PetSmart “all the time,” said Rachel Bellis, a manager of local affairs for PETA’s cruelty investigations department.

Pet grooming is an unregulated industry and many groomers don’t actually have a license, Bellis added.

Cordova noted that 42 complaints filed by PetSmart customers with the website Consumer Affairs since 2010 cited animal injuries and sometimes death caused by the company’s grooming services.

“A lot of the grooming incidents where animals have died — been strangled to death by collars, died from heatstroke from being left in the drying chambers — they happen so often at these stores so we are always pushing for states to have stricter laws on (grooming) practices,” Bellis said.

Zier and Peacock’s lawsuit against PetSmart details the litany of complaints against the retailer. In May 2016, a customer reported that a PetSmart groomer cut his dog’s genitalia during a grooming session. Days later, another report was filed that said a PetSmart groomer “scalped” a dog, leaving it without any fur. The dog died from its injuries.

“We never had children together,” Zier said. “I hope people can understand, these are our children. We pray he doesn’t die in vain.”

Sarah Ravani is a San Francisco Chronicle staff writer. Email: sravani@sfchronicle.com Twiter: @SarRavani