HACKENSACK, N.J. (CBSNewYork) – New video shows a disturbing dispute inside a Staples store in Hackensack, New Jersey.

Investigators say it started when a woman who uses a cane asked another customer to put on a face covering Wednesday afternoon.

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The victim, Margot Kagan, underwent a liver transplant just four months ago and suffered a broken tibia from the assault, CBS2’s Jessica Layton reported Friday.

“It’s really, actually quite painful,” said Kagan

Kagan, who was at the fax machine at the store on Hackensack Avenue, is particularly concerned about COVID-19 because she’s immunocompromised.

“There was a woman on the other side of the COVID dividers that they have everywhere now, and she wasn’t wearing it either. She was wearing it below her chin,” said Kagan.

Signs outside the store say masks are required to enter. It’s also required by the state. When Kagan reminded the woman of the rules, she paid an unexpected prices.

“I said, ‘You should really put on your mask,'” said Kagan. “She proceeded to curse at me.”

Police said the irate suspect didn’t just scream obscenities. Surveillance video shows she picked up the victim’s walking cane before forcefully grabbing it and throwing her to the ground.

The plastic partition, meant to protect customers, crashed to the floor.

According to Kagan, she asked another person to put on his mask moments before the incident and there were no problems.

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“He was wearing it below the nose and I asked him to put it up, and he put it up,” said Kagan.

Store employees wouldn’t answer any questions, including why from the video it looked like nobody helped the victim on the floor.

Other New Jersey residents reacted to the incident.

“That is astonishing. People know that this virus is very contagious and if they’re not willing to help protect everybody else, they should just stay home,” said Giavanna Deus, of Teaneck.

“It’s terrible. It’s terrible,” Ed Allen, of Hackensack, said.

It’s certainly not the first time there have been reports of aggression over a mask issue.

In June, a woman was coughed on by a stranger at an Astoria coffee shop after pointing out that her face was uncovered at the counter.

In July, police say a man punched an MTA bus driver after he was asked to wear a mask on the bus.

Police say they’re still trying to track down the suspect in Wednesday’s incident.

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Anyone with information is asked to contact Hackensack Police at (201) 646-7777. You can also submit an anonymous tip by CLICKING HERE or calling (844) 466-6789