A UCLA grad student was fatally stabbed by a random maniac while she was working as a consultant at a high-end furniture store in Los Angeles, police said.

Brianna Kupfer, 24, was alone and working at Croft House on North La Brea Avenue at around 1:50 p.m. on Jan. 13 when a stranger walked in and knifed her to death, according to the Los Angeles Police Department.

The unknown male suspect, who is believed to be homeless, then fled through the back door and walked calmly down an alley, cops said.

Kupfer, of Pacific Palisades, was discovered dead on the floor by a customer about 20 minutes later.

The victim was studying architectural design and worked at the furniture store as a design consultant.

Her distraught dad, Todd Kupfer, said Brianna had been set to fly out to New York late Thursday evening to celebrate a friend’s birthday — but was killed just a few hours before her flight.

The father said Brianna had a passion for dancing, a focus on sustaining the environment and was loved by all her family and friends.

“She always wanted to make sure everyone around her was having a good time,” he said in a tearful interview with The Post on Monday.

He slammed local politicians as too lenient, saying crime has been rampant. Over the weekend, LA officials announced a nearly 12 percent jump in homicides in 2021 from the year prior.

“I think our city leaders need to make smarter decisions about what they do with criminals and how they incarcerate them,” he told The Post on Monday. “I get it, there is a lot of racial injustice. But it doesn’t change the fact that somebody who is doing evil shouldn’t just get a slap on the wrist. Unfortunately, this is what we are seeing now.”

Riley Rea, a co-owner of the Croft House furniture store, said Kupfer had been working there for just over a year.

“I’m absolutely devastated for her and her family,” Rea told The Los Angeles Times. “It just seems so disgusting and unexpected. Really there are no words to say how shocked we are to lose such a wonderful person.”

Dr. Jennifer Botelho, the owner of a nearby chiropractic office, said that the suspect walked into her business shortly before the fatal stabbing.

“He came in and asked a couple of questions: ‘Do you do orthopedics here?’ What kind of care we provide, and then he left. So he was just here for a few minutes,” Botelho told CBSLA.

“It’s terrifying. It’s horrible,” Botelho added of the random daytime slaying. “She’s such a young girl. We feel so horrible for Brianna’s family, and hope we can catch this guy.”

No motive has been provided yet for the horrifying attack and police were still searching for the suspect as of Monday evening.

He was last seen on surveillance footage going north in the alley to the rear of the crime scene, wearing a dark hoody, sunglasses, a white N-95 mask, dark skinny jeans and dark shoes.