Ms Kupfer, 24, was alone on a shift at the Croft House showroom in Hancock Park on 13 January when a masked man walked in and attacked her.
Five days later, the Los Angeles Police Department identified Mr Smith as her killer, who was seen on surveillance video leaving the store through a backdoor.
Mr Smith is considered “armed and dangerous”, and anyone who sees him has been urged to call 911 immediately.
A $250,000 reward is on offer for information leading to his arrest.
Who is Shawn Laval Smith?
Mr Smith is said to have a lengthy rap sheet spanning the US from South Carolina to California.
His most recent arrest was for shoplifting, according to Fox News. He was also jailed in San Mateo for assaulting a police officer, the outlet reported.
Los Angeles County jail records also showed an October 2020 arrest on a misdemeanour charge. He was released on $1,000 bail in that case, the outcome of which was not immediately clear.
Before that case, records reportedly showed Mr Smith was arrested in Charleston, South Carolina, on suspicion of firing a weapon into an occupied vehicle in November 2019. He was released on $50,000 bond in that case.
He also reportedly faced multiple arrests in Cherokee, North Carolina, between 2015 and 2018.
Prior to Mr Smith being named in connection with the Kupfer case, police said they believed the assailant was homeless.
He was described as 6 feet 2 inches tall and weighing about 190 pounds.
Alleged connection to the Kupfer case
Investigators believe Mr Smith entered the Croft House store on La Brea Avenue at around 1.30pm on 13 January and stabbed Ms Kupfer to death with a knife.
She was found bleeding out on the floor by a customer 20 minutes later and was pronounced dead at the scene.
LAPD Lt John Radtke told the media on Tuesday that Kupfer had texted her friend to say that a man was making her uncomfortable moments before she was killed.
“She sent a text to a friend letting her know that there was someone inside the location that was giving her a bad vibe,” he said, adding that the friend did not immediately see the message.
Surveillance video purportedly showed the suspect leaving the store through the back and walking calmly down an alley wearing a face mask, backpack and dark clothing.
About half an hour later, another surveillance camera captured Mr Smith purchasing a vape pen at a 7-Eleven.
Police said Mr Smith has been known to frequent many areas of Southern California, including Pasadena, Santa Monica, West Hollywood, Covina and San Diego.
Los Angeles City Councilman Paul Koretz on Tuesday urged other city leaders to add $50,000 more to the $200,000 reward for information leading to the capture of the suspect.
“We will find this vicious criminal, we will arrest him and we will get him prosecuted to the fullest extent of the law,” he said.
“But we must fight for justice for her even though nothing will bring her back. Our mission and my objective is that the perpetrator that took away Brianna from her beloved parents, colleagues, friends and our community will be permanently locked away, constantly reminded of his horrible, ugly and senseless murder of an innocent young woman who had endless potential.”
Anyone with information is urged to contact West Bureau Homicide investigators at (213) 382-9470 or Crime Stoppers by texting to phone number 274637 (C-R-I-M-E-S on most keypads) with a cell phone.
Register for free to continue reading
Registration is a free and easy way to support our truly independent journalism
By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists
Already have an account? sign in