The head of a Harvard-linked research center is being ridiculed as “Sidewalk Susie” after a viral, cringe-worthy video caught the woman trying to order a mom and her biracial child to get away from her home and then condescendingly asking the family if they live in “affordable housing.”

The confrontation happened Saturday in Cambridge when Theresa Lund – executive director of the Harvard Humanitarian Initiative – came out of her apartment to complain about noise allegedly being made by Alyson Laliberte’s toddler on the sidewalk outside the building.

Laliberte recorded the confrontation and posted it on Facebook.

“I’m sitting here because you’re preventing my children from sleeping. Would you like me to do that to your kids?” said Lund, wearing a purple T-shirt, running shorts and her hair tied back.

Laliberte answered: “Who is even watching your kids right now. Are you? Cause you’re not, you’re here with me and my kid.”

That’s when Lund, who is white, accused Laliberte of being poor.

“Are you one of the affordable units? Or are you one of the Harvard units?” Lund said in the video that’s been viewed more than 9,500 times by Monday night.

Laliberte kept her cool in the video – but then let Lund have it on Facebook.

“It was totally discriminating and racist of her.. or maybe it was because my daughter is biracial who knows,” Laliberte wrote on Facebook.

“I I have no idea who this woman is and the fact that she thinks she has some kind of authority over me is crazy!”

The incident is the latest in a string of confrontations involving a white person accusing a black person of not belonging in a particular setting.

In an email to the Boston Globe, Lund admitted she behaved poorly.

“I want to be accountable for my actions in a situation where I fell far short of my values and what I expect of myself,” Lund said. “This clearly wasn’t my best moment, and I have work to do to more consistently be my best self.”

The Harvard Humanitarian Initiative bills itself as a research center aimed at “relieving human suffering” brought on by war or disaster.

Lund’s bio was not on the group’s website on Monday night.