Lopez, an alleged gang member who spent time in prison for false imprisonment, and unidentified woman entered the liquor store about 10:43 p.m. June 17 and walked to the beer cooler, according to police reports.
Lopez grabbed a 12-pack of beer, two 40-ounce bottles of Locos beer and a juice from the cooler, before asking the 18-year-old store clerk for a pack of cigarettes, police said.
The clerk rang up the purchase, but Lopez told him to "put it on my credit," according to the report.
The store doesn't keep tabs or credit lines for customer, the store owner told police.
Lopez then exited the store without paying and the clerk followed him, asking him to pay for his purchase.
That's when Lopez allegedly turned to the clerk and said, "You are going to come after me? Well, come on," according to the police report.
The clerk did not immediately report the incident out of fear of gang retaliation, according to the report.
But after the clerk and store owner reviewed video footage of the incident, they opted to contact police.
The June 17 robbery is the third to occur in the city in past week.
An armed robber stole $500 from a Chinese restaurant June 18 at gunpoint, Sgt. Tom Lorenz said.
In that incident, the man pointed a gun at the clerk's head while grabbing money from the open drawer. He then ran from the restaurant as the employee hid inside, Lorenz said.
And on Monday, three men robbed a Chevron gas station owner at knifepoint.
The men approached the gas station owner while he was inside his car, smashed a back window and brandished a knife, police said.
A store employee said the thieves stole a bag containing about $50,000 in receipts and cash.
Anyone with information on the robberies may call the Robbery-Homicide Unit at (818) 548-3487. To remain anonymous, call the Los Angeles Regional Crime Stoppers' tip line at (800) 222-TIPS.