Police were quick to reassure the public that the shooting at Fisherman's Wharf was an isolated event.
"I don't know what the dispute was about, but it was between merchants," said SFPD Spokesman Lt. Troy Dangerfield.
Two people were gunned down inside the store on Jefferson Street, right next to Joe's Crab Shack, at 8:20 Sunday night - when the wharf was full of tourists. But police say they feel confident the person they arrested acted alone and that tourists can feel safe. And by the looks of things -- tourists appeared ready to move on.
"I love this area. We have shootings at home in Detroit. I feel safe. I'm out running at five in the morning," said Tony Phillips.
It's the merchants who are feeling a bit uneasy today, despite reassurances from police.
"Fisherman's Wharf doesn't seem safe. I'm scared to be working here already. I'm happy to hear it wasn't a robbery, but it's still scary," said store clerk Eric Manley.
Police say it appears the fight was over who can sell what merchandise and at what price. Workers on Jefferson Street say the competition for the tourist dollar can be intense.
"The landlords try to keep it separated. You can notice a pattern if you walk down Fisherman's Wharf, there is camera store, t-shirt store, luggage store - things like that. So there is competition where they do try to keep it separated, but I've never seen violence," said Manley.
"I'm shocked because I have a new daughter, so for me it's not safe to work here," said Jason Cu.
Jason Cu says the woman who was killed was very friendly and cheerful. He can't believe he won't be seeing her at her shop anymore.
"When you're used to seeing the people - like six years she's been working here and I see her everyday and suddenly something happened and you just talked to her less than 24 hours (ago) - the feeling is creepy," said Cu.
The store on Jefferson Street is still closed. Police aren't sure where the suspect worked. He may have been selling items out on the sidewalk. His name has not been released. The two victims are Qiong Han Chu, a 30-year-old man, and Feng Ping Ou, a 30-year-old woman. Based on what the suspect has told investigators, they believe he is the killer and he acted alone.