Since November, the suspect has struck 13 times, mostly at Walgreens and CVS stores. Investigators say he's picking up his pace - he's robbed four stores in the past two weeks.
At the CVS in Carson, the suspect was caught on surveillance video entering the store just before closing time. The automatic opener for the front door was already turned off, but a worker let the suspect in. The man did little to hide his identity.
"Maybe he works in the construction business or maybe a road crew where he needs to wear the safety vest. There's really not a need for him to wear it to gain entry," said sheriff's Detective Richard Alvarado.
Alvarado says the robber wore the reflective vest for the first seven of his holdups, but has since dumped it on his last six jobs.
In all the robberies, the suspect brandishes a black semi-automatic handgun. Investigators say he's becoming more brazen.
"If someone knows this individual, they will recognize him. He's not concealing his face, he wears a ball cap, but that's about it," Alvarado said.
Alvarado says the robber typically goes to the store's liquor aisle, grabs a 12 pack of beer and robs the store once the cashier rings up the sale and opens the register. Then, he calmly walks out of the store.
The suspect was described as a black man between the age of 35 and 45, 6' to 6'2" with a thin to medium frame and salt-and-pepper hair. He was seen in a light-colored, late-model compact SUV, Alvarado said.
Anyone with information is urged to call the L.A. County Sheriff's Department's Major Crimes Bureau at (562) 946-7893.