Police say they dealt with a series of these robberies last summer, and now it's happening again.
The latest happened at 21st Century Jewelry at 749 South Broadway last Friday at about 1 p.m. Security video shows three robbers wearing red hoodies running into the store and smashing the glass display case.
"They come in, hit the cases, use intimidation, or in this case ... pepper spray," said LAPD Lt. Paul Vernon.
After grabbing about $7,000 worth of costume jewelry, they escaped in a waiting getaway car.
Police say there have been a series of smash-and-grab robberies at jewelry stores along Broadway, and investigators believe the crimes are being committed by crews of robbers from several South L.A. gangs.
"It's something that we've seen a pattern of now for the last six to eight weeks," Vernon said. "Part of it is motivated by the price of gold."
Vernon said 13 people have been arrested in seven recent smash-and-grab robberies.
Police say stores that are most vulnerable are those with display cases close to the front door, while stores with security guards are less likely to get hit.
Anyone with information is urged to call the LAPD Central Station at (213) 972-1251.