19-year-old Matthew Owyang was formally charged Thursday with the two murders outside a pizza shop on Irving and 19th Avenue.
Jason de la Cruz and Derek Butch were both shot to death early Saturday morning outside the restaurant.
De la Cruz managed a Verizon cell phone store in Daly City. He was celebrating a good month by treating his sales team to pizza.
A witness says another customer then demanded free food.
The argument reportedly spilled outside when someone in a car opened fire.
On Tuesday, investigators arrested Owyang at his Daly City home.
Police say witnesses helped break the case, but Owyang's attorney Bill Fazio says police arrested the wrong person.
He says only one witness is quoted in the police report and her recall is shaky.
"One young woman identified my client as possibly the suspect. To quote her, "it looks most like the shooter."
District Attorney Kamala Harris declined to talk about the case because it's an open investigation, but she says investigators are still looking for witnesses.
"I absolutely encourage anyone out there who has evidence about this case to do their part and stand up," said District Attorney Harris.
Aside from these tributes to the victims, busy Irving Street is back to normal, all except the pizza shop.
Attorney Eric Safire represents the owner who says the murders have hurt his business.
"It's an unfortunate circumstance for him because he see's his place of business as being depicted as some sort of place where crimes take place and it's not. It's a family, well run business," said Safire.
Although District Attorney Harris declined to talk about the case, a law enforcement source tells ABC7, police recovered a handgun which they believe was used in the murders. The source did not say if the weapon has been linked to Owyang.